Whoopsie. Got a little on your chin there.
The question posed is "Which one will fill up first"? Since there is only one '1', 1 it is.
Either #1 or #5. Note #4 has a hole in the bottom, and the pipe to #3 hits a solid wall. However since 5 has no top if it fills up it will just overflow and the rest won't fill (unless the entire room floods). But, if the water comes out of the faucet much faster than it can drain out of the pipe from #1, then #1 may fill up and overflow first.
I still remember a college psych class where the prof told us "never take a paranoid schizophrenic to a football game"