ITT:

why is this even on Veeky Forums
its 7 you dolts

7 has a hole in its bottom

Because logic puzzles are fun. The actual meme probably says some stupid shit like, "None of themm! because hura;lksjdfkljsnudf the faucts' not truend owwwwnnnnnn!"

ITS THREE LOOK

T H R E E

nigga someone tell me why it ain't 4

Paths are sealed.

Because the pipe going from 3 to 4 is sealed. Also, the other pipe to the right of 3 is sealed (Little lines there).
Shoutouts to OP giving us something that merely takes longer to look at and zoom in on the pic that doesn't prove IQ

...

3, obviously, after filling the sealed tube to 5 it will continue to fill.