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 answer questions in the form of a question. This is a requirement in Jeopardy, and has been since its beginning.
In case of the question, the answer should be “What is the Eiffel Tower?”, but that’s a grammatical thing.