Awkward title probably, but lemme explain:
The question is “This piece of French architecture was finished on January 26, 1887.” You know this is the Eiffel Tower. But when you buzz in and give the response, you say:
“Who is the Eiffel Tower?”
Would you be awarded the points for being correct, or docked the points for being incorrect since you didn’t say “WHAT is the Eiffel Tower?”
You have to phrase it as a question to get the money. When you buzz in you get something odd like 7 seconds to answer the question. If you just say “Eiffel Tower” then Ken Jennings will now probably just stare at you expectingly to rephrase your reply in that time. I think in the past Alex Trebek may have prompted candidates to rephrase their non-question answers but I haven’t seen that happening in a while (but I don’t watch it that regularly either so 🧂).
The whole point of the show is that the standard quiz show mechanic question->answer gets put on its head. The clue on the wall is the answer and the candidates have to provide a question it answers.