My favorite are some of the work systems that I need to access, but only infrequently, yet still have ridiculous password expiration rules. Nearly every time I log in, before I can access the system I have to change my password because of course it's expired again. So I change the password, write it down because I'll never remember it months from now when I need to use that password exactly once to login and change my password yet again.
What they are doing is comparing your answer and seeing if it is consistent with how it has been answered previously. They realize that not everyone is going to give the exact same answer, so as long as you answer it in a way that enough other people have answered it, it should let you in.
I'll usually go with the minimum number of clicks that I think will get me through, since I'm lazy and it'll also at times slow down how fast you can click which is annoying.
I'll also answer them wrong if I think it's a mistake that enough other people will make. "Yes... that RV over there is a bus..."