What is the Hardest Level in Geometry Dash?

Been a while since I made a research like this.
▶ FOOTAGE USED:
• RobTop - Geometry Dash Trailer: • Official Geometry Dash...
• NPesta - Kenos: • KENOS VERIFIED (Extrem...
• SpaceUK - Slaughterhouse: • Video
• Nexus - Tnanatophobia: • (Extreme Demon) ''Than...
• Trick - Firework: • "Firework" VERIFIED! (...
• Dolphy - Tartarus: • TARTARUS VERIFIED! By ...
• Baeru - Trueffet: • [EXTREME DEMON] Trueff...
• Fossa - Flame: • (Verified) Flame By Fl...
• NcaT - Spitting Bar: • Spitting Bar 100%! [We...
• Zamasu - Delusion: • DELUSION VERIFIED (Top...
• Yossarian - VSC: • VSC VERIFIED (Top 1 Ch...
• Vitesse - Silent Clubstep: • Unnerfed Silent Clubst...
• Luqualizer - Silent Club: • Geometry Dash - Silent...
• Zynvire - Silent Circles: • SILENT CIRCLES IS COMP...
• Cursed - Sakupen Circles: • Sakupen Circles 69% //...
▶MUSIC USED:
• Not For Nothing, Otis McDonald: goo.gl/piodvb
• Not Too Cray, Huma-Huma: goo.gl/cNsHB9
• Coming Home, Reasoner: www.newgrounds.com/audio/list...
▶Texture Pack (GD): mega.nz/#!QpIhXYDQ!AUp9BDxV8d...
▶Texture Pack (Minecraft): minecraft-resourcepacks.com/t...
▶RadicalMania (My osu!mania Channel): kzbin.info/door/yFs...
▶ PC SPECS:
• SYSTEM: Windows 10 Pro 64-bit Operating System
• MONITOR: BenQ XL2411Z [144HZ]
• PROCESSOR: IntelCore i7 8700K CPU (@3.70GHz)
• RAM: 16GB
• GRAPHICS CARD: NVidia GTX 1080 Graphics
▶ Software:
• Recording: OBS Studio
• Editing: Sony Vegas Pro 16
• Graphical Design: Adobe Photoshop CS6
▶ Other Specs:
• Mouse: Logitech G502
• Keyboard: Razer Blackwidow Chroma
• Microphone: Blue Yeti
▶Sources:
• Thumbnail made by: Crazey# 4859
• Profile Picture made by: Lexicon (Lexicon# 7605)
• Banner made by: Lexicon (Lexicon# 7605)
▶Social Media:
• KZbin: Alias (You're already here though)
• Discord: alias# 4104
• Twitter: @gdalias_
• Snapchat: swagetiyoloneze (I was 12 when I named it that, don't judge me)
Thank you so much for watching! If you scrolled all the way to the bottom of this description, you deserve a cookie. Or two. 🍪🍪

[@jochom1163]

Every level in the HLL: *DOUBT.* don't take this serious.

[@miners_haven]

The TPLL:

[@rainbowserial]

@@miners_haven most tpll levels break game engine limits

[@plushiibean]

Whats the hll and tpll

[@miners_haven]

@@plushiibean The HLL is a list of the Hardest Levels, and the TPLL is a list of the hardest Theoretically Possible Levels

[@grkebab]

how about sll

[@Birbzz]

As someone who passed Stereo Madness in practice mode, I can confidently state Demon difficulty is pretty simple

[@jennycummins302]

Wdym you suck btw I now your joking and I am joking

[@441Saadxgirl]

Yeee i do it for 4673 attemps, demon is very easy.

[@fabriciosinoti7983]

Bro only 4673??? I did It in 999999999999999 att😭

[@441Saadxgirl]

@@fabriciosinoti7983 sad *_*

[@Birbzz]

@@441Saadxgirl ayo that’s a pure WR!

[@lightyfr9881]

when "To the end of time" by Hyperbola will come out, we will truly have something that cannot be any harder

[@nta186]

Physically impossible because of the xpos, also gd can go above the fps required for tteot

[@SoziFang64]

Then Dolorem aeterna x2147483647 will release

[@Anxmaly666]

1000fps players in 2025: Hold my cube

[@extremeexployer]

Pamka Never Clear X requires ~f_ψ_0(Ω_ω)(100)clicks. Amount of clicks in TtEoT is nothing compared to this

[@nta186]

@@extremeexployer my bad, i havent seen TPLL list in a long time i just saw lmfao

[@SpaceKadet1454]

The irony of him showing Silent Clubstep as one that will never be completed. You were right Alias, GD’s skill level will continue to sky rocket.

[@BlockingBelow]

Yeaa, it happened

[@HyperNova808]

Everybody gangster till nessus is verified.

[@matuskusnir3140]

7:36 ah yes impossible levels has been popular around year 1920

[@tbgng]

Watching this during the premiere. I'd guess it was slaughterhouse or one of those old impossible levels that are possible now

[@realm3525]

i mean the old version is humanly impossble

[@omnivex9504]

LMAO - ‘or’ - mate it’s the same thing you might aswell have just said the second part

[@tbgng]

@@omnivex9504 i mean like sakupen circles or silent club

[@omnivex9504]

@@tbgng Ik it’s just the fact that you said slaughterhouse or ‘ ’ when slaughterhouse was one of those levels that used to be impossible

[@duck_mcfuddle]

I’m pretty sure VSC is still considered significantly harder than SH, and maybe even Sakupen Circles

[@theprez7022]

"Sakupen Circles, if this level was to ever be rated it would be the hardest rated level" Famous last words.

[@rhymingdood7178]

it really happened

[@Veetamin__GD]

Ayo what

[@superseriousperson3729]

not anymore

[@Veetamin__GD]

Well, umh, nevermind

[@rhymingdood7178]

@@superseriousperson3729 my comment aged like milk

[@leonardobagi9353]

I Really enjoy the way you make this kind of videos. Keep on doing more of these, they are very entertaining :>

[@xejux4928]

7:36 in 1920 : bro i want to do an impossible level

[@frisukeurahara1322]

You will need a part 2 for impossible levels. Such as dolorem aeterna, suffer, tower, ballistic wistfully, and many others in the silent/impossible levels list.

[@rumanaafrin3594]

Ballisctic Wistfully IS the hardest level (that is beatable)

[@pojfgdlkfgjgdlkfg6912]

@@rumanaafrin3594 I thought schafs ii is harder

[@MinusZaxis]

@@rumanaafrin3594 nope

[@Ezekia]

@@MinusZaxis schafs ii is listen above bw im pretty sure

[@Astr08099]

@@rumanaafrin3594 nope

[@jotzyjostrazar5817]

The real question is if we considered "Hardest" as "The hardest level beatable" or "The hardest theorically thing possible". There are tons of level, like Ballistic Wisfully, that, despite being considered "Possible" due to the fact that are "Physically possible" aren't possible humanly for a lot of reason, the first being perfectly precise and click and the exact frame for more than 3 minutes, this kind of a perfection can't be simply accomplished by anyone so this means, if we consider "Hardest" as the "Hardest level that a player can beat" that there are basically no difference in term of difficutly between "Sad Santa" and "Schaf II" because both aren't "Harder" but simply "Impossible to be accomplished". I think that, for find what is it the hardest possible level that is theorically beatable by an human (not by a bot) we just need to see something around TOP 75-100 in the "Impossible level list" because, despite being extremely precise, that kind of levels actually don't need a perfect precision throught 2-3 minutes. All that for saying that: in my opinion the hardest level humanly possible (if we consider some bugs like being able to jump three spikes in half speed) is something arounf Death Corridor and Silent Acropolis.

[@dyzpervolkz2386]

silent acroWHAT D:

[@samsungsaiyam1090]

No one’s going to read that….

[@duggie311]

@@samsungsaiyam1090 I did

[@duggie311]

My man's wrote a whole essay

[@samsungsaiyam1090]

@@duggie311 damm

[@pxdmc.]

im still feel bad for knobbel and bloodlust lmao, imagine spending 1.5 years to verify it just to get knock out of the top 10 by a very trash gameplay/deco silent level loll

[@jpmunzi6799]

Everyone knows that the hardest level ever is sakupen wall, even with botting nobody have ever beated it, and it is only 4 second long

[@fifok2944]

xd

[@XTLmaker]

No its actually sakupen crash trigger

[@thunderchunky5650]

Nah the hardest level is unnamed 0, I struggled with it soo much

[@Henryy06]

@@thunderchunky5650 this is so hard that there are more than 100 of them

[@worldprops333]

it's mystic clubstep

[@imavirginm8264]

Hardest level is called tower of oblivion by illuminati. Edit: its now pamka never clear x

[@skeletonlolreal]

That level isnt physically possible. The hardest physically possible level is Shatter 2401 by Convindix

[@cactuspromc2730]

What about ton 618? you can't even pass the first spike

[@tytekfrytek]

nah its sakupen wall

[@nta186]

@@cactuspromc2730 physically imposible levels dont count here

[@cactuspromc2730]

@@nta186 Ok... But there's a spelling mistake in impossible

[@ideac.]

i love the new editing style its perfect, i hope to see more of that in the future

[@impr0v]

In premiere I was guessing the hardest POSSIBLE RATED LEVELS would be Slaughterhouse and Firework, and i guess I was kinda right since Slaughterhouse was there :) edit- DAMN OVER 90 LIKES tysm

[@sameeknowsitall]

Yes

[@podkast.mp3]

bruh you actually thinking those slaughterhouse and firework are hardest? if you think that it means that ur never played gd. actually the hardest possible level with normal gp is ballistic wistfully.

[@Yusuketh443]

@@podkast.mp3 lol

[@impr0v]

@@podkast.mp3 is it rated tho¿

[@seekmedicalhelp]

@@podkast.mp3 that level is not rated, not even beaten by a human...

[@Vedertesu]

Hardest level is the one where you need to click every single planck time, I dont remember name of that level tho

[@kidronnie4456]

i think it was called tower

[@gdstar6917]

the hardest level is To The End Of Time by Hyperbola

[@maybe-arch]

God that’s insnae

[@grammienoob2997]

either tower or to the end of time

[@Shneaky]

To the end of time

[@duck7405]

The fact that silent clubstep is now possible is crazy

[@ivantrubitsyn5t2tw69]

Thanks for making this video it was very interesting and you helped me understand the levels!😁

[@scemer771]

4:59 there are levels harder than VSC ant tartarus *shows stereo madness*

[@vterehov13]

hardest level in geometry dash: *unnamed 0*

[@amongous6913]

ton 318 is the hardest EVER slaughterhouse is cute

[@uctrinh5341]

Dude its not even compared to dolorem aeterna

[@everybodyclapyohands]

sakupen wall the wall by cyclic or cyrillic are not hard

[@ep1k_4]

No it's unnamed 0 copyable

[@everybodyclapyohands]

@@amongous6913 ton 618* also its physiclly impossible no matter what

[@izzymosley1970]

I like to think that someday The impossible levels will be completed and when I think they're completed I don't think it means that the level was wrongly classified as impossible but I only think it means that people were able to get to a level of skill that was formally thought of as impossible

[@L9nexah]

Sakupen circles just got verified!

[@EvsUnderscore]

I hope someone has mentioned the impossible levels list already, it’s a list of impossible levels, (that are not physically impossible) they have a discord server with over 2k members

[@Fabled_Adventure_Girl_Kanna]

I hate how much the difficulty standard is so much higher then before, many stages for casual player like are really hard even though they are rated "harder". I hope that rob will also add new difficultys that will spread the range of difficulty for casual players.

[@sasdrob]

Imagine if there was a difficulty slider in GD, with very specific difficulty ratings, that would be cool

[@Fabled_Adventure_Girl_Kanna]

@@sasdrob thats actually an awesome idea

[@chair7713]

Dolorem aeterna is probably the hardest level ever. Someone could just make an extension and theoretically make it harder tho

[@anti7654]

That's not true,the hardest level is To The End Of Time by Hyperbola

[@zDeimos]

It’s deleted

[@nta186]

@@anti7654 Physically impossible

[@nta186]

Physically possible and also wouldnt even be the hardest

[@anti7654]

@@nta186 Tower then?

[@bu8ux]

3:43 your voice syncs with the level

[@corviknightor]

I love how he is talking about “the hardest levels” but sometimes just switches to stereo madness lol

[@Tr1Dylan]

I think firework is harder then slaughterhouse, but once again it varies person to person. I just think slaughter house has a much easier first 25%

[@shiver-charabii]

its probably that one level where you have to click 10^800 times in a few seconds but i dunno could be something else

[@srdino2335]

Tower by septagon7 I think it's harder

[@skyofquacks]

this level is physically impossible

[@Vedertesu]

Well, its not even theoretically possible because of real life physics

[@skyofquacks]

@@Vedertesu but a bot can register 10^800 inputs in a few seconds

[@nta186]

@@skyofquacks it isnt you change fps mid game

[@ygemkaa]

its only a couple of months since this video came out and it's already funny to see lol

[@aethergaming7934]

Super cool Vid. This is what got me into gd!

[@matiasvahervuori876]

4 months ago Norkbork released a video "What comes after Firework?" (Well, Slaughterhouse now since it's #1) and there he speculated that the unnerfed Silent Clubstep would be the hardest level ever if it gets verified. Yes, I'm not talking about the nerfed, more possible version people are trying to beat. THE unnerfed, original SCS

[@SpaceKadet1454]

It was verified my friend

[@fishdrip54]

@@SpaceKadet1454 the nerfed one

[@ryanmuckle8086]

*"Well done! Now try to complete the level without any checkpoints!"*

[@ifyousubtomeyourecool6244]

Honestly probably some map pack level deserves to be up here

[@therealatomic6170]

I think your top demon Icon should be for all these levels, which are tecnicaly possible, but so hard, that they aren‘t veryfied yet

[@pastrylol]

A 10 block high wall with no decor whatsoever: *are you a joke to me?*

[@fazbearlovescuphead862]

i’m still on level can’t let go 💀

[@plantwubboxgaming]

naw ur not the only one IM STILL ON BACK ON TRACK 💀💀💀💀💀💀

[@DogeplayzYT-74yi]

:skull

[@DogeplayzYT-74yi]

I finished

[@user-vc5pv8ow8r]

Nuh uh ur not gonna believe me I’m still on dry out🤫🧏‍♂️💀

[@Wh1t3ninja66]

We =

[@Yuvsters]

Slaughterhouse: IM GONNA BE THE HARDEST LEVEL ForEVER! Sakupen circles: hi

[@cheeseburgermonkey7104]

I can't believe a normally subjective adjective somehow morphed into an objective adjective in this game

[@mrgopnik5964]

Finding the limit to geometry dash difficulty is like finding the limit of the human mind. It’s basically impossible, since everything created by the human mind also lies within its perimeters and since the human mind constantly pushes those perimeters, the game just evolves with the mind. Thus finding the hardest level in Geometry dash is equivalent to anything from making the tastiest sandwich to creating the most effective government: every chef’s perfect sandwich will be outdone by the one who finds a better recipe, every perfect government will collapse under missmanagement and every level can be beaten if we try hard enough.

[@memesauce7703]

Wtf

[@Thenematicphase]

@@memesauce7703 hey kid, study philosophy

[@buitre332audaz5]

@mr Gopnik even things like dolorem aeterna and pamka never beat x? (pamka never beat x needs more clicks than TREE(3))

[@bryantofsomething5964]

What about nessus by ukarla?

[@s________________-.]

@@bryantofsomething5964 there is always a way to go further. always.

[@srdino2335]

The hardest level is tower by septagon7, its only possible at 22 trillion fps

[@user-gk6ih6hd6t]

...

[@JustKille]

Tower of oblivion.... Also he talks about humanly possible levels

[@kenos911]

@@JustKille hé doesn’t even bring up the hardest ones in that category

[@extremeexployer]

@@kenos911 tower of onlivion is physically possible. And hardest level is Pamka Never Clear X that requires ~f_ψ_0(Ω_ω)(100)clicks

[@srdino2335]

@@JustKille 6:55 🤨

[@vaporwingfauxmcloud1190]

There is one level I saw on a short on here that basically makes a level 1 haunted version of a demon level... the map changes mid game and confuses people because it can stay changed or it'll be back to Level 1... Or it was edited but it was scary and gave the streamer PTSD 😂

[@lord_mega5588]

I think old slaughterhouse (by iced cave) had literal impossible wave spam with up to 3x speed

[@WsWWCE]

Truly, the hardest level is back on track

[@JordanHaydooonbhg]

@Jyoti Naik joke

[@lina5640]

I couldnt even complete stereo madness

[@kaka88k1]

@@lina5640 i only could in practice

[@lina5640]

@@kaka88k1 but practice is super lagging u have to go to teh orher checkpoint

[@lina5640]

INCORRECT its dry out

[@rephix6724]

How about u do 2 bot runs, one with every click as early as possible and one as late as possible. then u look how many frames u have for each click so u can tell how hard the lvl objectively is, or wouldn't that work?

[@utubeiskaren7796]

Dolorem aeterna is 8 hours of frame perfect imputs every single frame at the game’s maximum FPS.

[@Astr08099]

@@utubeiskaren7796 but due to the xpos limit it is physically impossible

[@Saturn_57]

Imagine seeing this video in like 30 years later, and then slaughterhouse is like top 50

[@heroplaygames2012]

Accualy, we know. There a impossible levels list (ILL) but it contains levels that have up to 15 cps spam. Theres Silent levels list (SLL) which contains levels with that have spam over 15 cps. The highest level on SLL is Suffee by vinci

[@monkey6114]

One of the hardest imposible level is old death coridor and the WR IS 39%

[@fndjxhf]

And so we have our answer, or do we? Vsauce music intensifies

[@Sahlokniir325]

the hydra myth sort of thing isn't just limited to Geometry Dash, other games would also have this sort of concept, one of them is with mods

[@slugsxx]

A new Silent Clubstep was made, with NO gameplay changes/nerfs and will be verified legit as far as i know

[@RinkieGeintie]

Hardest one isnt tower or dolorem anthena, but to the end of time by hyperbola. You have to click with every player every planck time, the smallest time chunck the universe can advance by. And that for 37 hours long. On top of that, there is a countrr at the end of the levels, which only lets you through if you beat it (2^49)-1 times.

[@bryantofsomething5964]

No it’s nessus by ukarla

[@TheNoise955]

@@bryantofsomething5964 OMG BRO WE ARE TALKING ABOUT HARDEST LEVELS NOT LONGEST LEVELS NESSUS IS A LONG LEVEL AND THE UNIVERSE WILL DIE OMG ITS EXASPERATION AND IF YOU SAY NoT eVeN cLoSe THEN YOU HAVE NO BRAIN

[@blubby8932]

there’s an upcoming memory demon called limbo that is top 1-3 difficulty. it’s comparable to all top 3 demons. i would not call it the hardest however, since memory levels really just matter on the players memory.

[@aeiouuioea]

Heres the top 5 hardest levels lmao 1. doki buys weed 4k ~fψ(ψI(ω,0)(0))(2^32) clicks 2. THMarisa fΨ(Ωω)(520) clicks 3. PNCX fΨ(Ωω)(100) clicks 4. Outerversal ~fφ(ω,0)+ω+1(777²) clicks 5. Tower of Oblivion ~fφ(ω,0)(999) clicks *these are only theoretical.*

[@VinetusYT]

Woah

[@tigereye22]

Everyone: nothing could be harder That one person: nah gonna make and verify something impossible

[@id2al]

Alias: if sakupen circles gets legitimately verified it will be the hardest level Me from the future: hmm i would have never thought of that happening, HE KNEW ALL ALONG

[@KingstonDaGoat]

YESSS ITS VERIFIES WOOHOOOO 😎

[@cursed7474]

This level is so hard that you have to click exactly at the midpoint of the strings of the String Theory, and click faster than the speed of the expansion of the Universe. *Back on Track 69*

[@averagelizard2489]

TPLL Levels: *silently laughing*

[@damarzrealm7731]

Hardest levels are those that are filled with so many blocks at the start that u can’t even open them, and therefore, can’t beat the level

[@Yelowmoonmastergd]

0:26 that means as of 2024, players are almost 38.443359375x better than in 2015 when riot verified bloodbath

[@BigHotGarbage]

Hardest level is Balls in Your Jaws by MantaBoy21

[@alexshorts7395]

Hardest level is stero madness. That 3 spike tho 😔

[@pannnella]

HAHAHA. no

[@WatercraftGames]

ye

[@s1olereal]

unfunny

[@randomtrigger4363]

true i actually struggle on triples

[@Casper10NY]

This is the video that inspired me to download geometry dash 2 years ago. Thank you alias.

[@yorickcool15thegamer33]

Next: What is the most popular level in Geometry Dash?

[@imakevideos30408]

Retray

[@lumi2030]

hardest level is pamka never clear x by me and eulernum. more than TREE(3) clicks

[@bryantofsomething5964]

I was going to say that but i forgot how to spell pamka

[@lumi2030]

@@bryantofsomething5964 how did you forget that lol

[@bryantofsomething5964]

@@lumi2030 idk

[@minecrash101]

Did not hear one back on track joke, disliked unsubbed

[@awadont]

Tartarus was dethroned 4 times, the 3 you mention and when The Golden was for some reason higher in the demon list

[@siddiqgamesyt3354]

"Silent Clubstep is impossible" Paqoe: My honest reaction to that information

[@flytude]

thanks for explaining the silent thingy tho, thanks really much

[@ggezwinmustbelike8544]

Fun fact: hardest level is Nessus

[@fifok2944]

I like how he puts clips of dolphy's video from silent circles but he don't talk about this level

[@fadezz7217]

No, theres not 60 million NA levels, that was the level ID just so you know. Great video!:)

[@HakiWaki]

the level id number corresponds to the number of levels that have ever been published, counting deleted ones, so we dont know how many levels there actually are, but we know that the highest id number is actually how many levels have been created.

[@HakiWaki]

so yes there are tens of millions of levels

[@Casper-qy4wg]

This was the video that made me play geometry dash. Thank you alias.

[@daviliad2636]

actually, i think in the pyramid insanes shoudl be on the same tier as the NA's, since "impossible" levels cant be demon or rated

[@pmmgaming9401]

alias a month later when silent circles gets verified: Oh fu-

[@prime2357]

how did you make this video without mentioning the Impossible Levels List or Silent Levels List

[@jotarokujo6440]

Only OGs remember when Knobbelboy beat Bloodlust and it was the hardest level in the game.

[@buzzybees8604]

"Firework and Slaughterhouse, which are both harder than Tartarus and were verified legitimately"... That aged like milk

[@ryaneiler5709]

there is actually a list similar to pointercrate demonslist but for the impossible ones

[@whyistherebossmusic7406]

Wow I'd forgotten how long it took the community to beat silent clubstep

[@ystualt7272]

What about impossible level list or silent level list?

[@MinusZaxis]

As a impossible level enthusiast, i feel physical and mental pain after reading the comments

[@scottc2076]

What about is slaughterhouse or firework harder?

[@dumb_4933]

when he said sakupen circles would be the hardest level in the game it currently sits at no.2 on the demon list behind slaughterhouse

[@thecyryl]

right now technically the hardest physically (not humanly) possible level is quantum entanglement (the cps required is so high the energy created out of your clicks (if you did it, which you can't) would literally create a black hole in your own house)

[@cybercat7851]

Well, there’s a lot of gray area there. I just watched slaughterhouse and it has almost hit box perfect wave, so I think its harden than circles

[@xfnblazelol4923]

I came back to this game after about 2 years and I beat Viking arena

[@rexperverziff]

Tartarus: *gets beaten* Riot: Geometry Dash, use New Level!

[@Justfun-kh4kn]

Took me 7 months to beat something that normally takes 2 years wow.

[@presidentduck1355]

So if impossible levels will be beaten eventually... Alr time to get started on Ballistic Wistfully

[@KingstonDaGoat]

sakupen circles took over tartarus firework and slaughterhouse. for people in 2022

[@callsigncustard65]

I know that eventually the limit will be reached but will we ever actually find this limit

[@C_Rest]

Epic vid, Keep it up!

[@shockedgaming8391]

3:30 and so we have our answer *shows stereo madness* but do we really

[@matgemblung5968]

maybe part 2? you gotta include limbo after its verified and uploaded

[@fortheconguitos]

Ain't nobody gonna talk about that swag route at 0:14 ?

[@ThePrimeYeeter]

pamka never clear x: we do a little trolling here😎

[@susickanahousky4119]

Why is no one talking about the invisible sunset sandstorm and the invisible black blizzard. I know they are probably not as hard as VSC, but still, they deserve a mention in the not rated difficulty list

[@The_CubingManiac]

1:35 smiffy777 has the ship that basically everyone uses

[@theholyvuelaytx924]

Fun fact: unrated insane is the actual hardest difficulty in game, being the hardest non featured difficulty which isnt really that hard to get, and also ALL the impossible levels have the unfeatured insane difficulty, making this the hardest difficulty of GD.