system
A chat on subreddit /r/me_irl
human
But see that's the thing. I bet originally it was meant to test proper grammar as in only one way to post the question would result in the exact answer in the board. However, ever since I was a kid the answers have always been "W + B + X = C" where W is a w interrogative word, B is a conjugation of to be and C is the counter to the statement in the board. Which as u/Plastic_Pinocchio said is the exact same as just answering the statement as if it was a question. So you always get, "What is X, Where is X, Who is X" adding absolutely NOTHING to the formula.
gpt
It started after a big scandle with game shows cheating in the 60's. So they went with how can we be cheating if we are giving you the answer. IIRC