This riddle gimmick is incredibly stupid. There isn't one correct answer to a question like that, not to mention a way of verifying that such a colloquial test even has a "correct" answer, which means the person that made it gets to choose whatever answer they personally prefer. That of course means they can just choose something super obscure that nobody would ever guess. In the first place, though, there isn't even a reason for the riddle to exist rather than just a trapdoor that kills everything.