Think questions where there is a ton of existing medical research, but no clear answer yet. There are a dozen alzheimer's questions you could for example ask which would require it to pull in a half dozen contradictory sources into a plausible hypothesis. If you have studied alzheimer's extensively it is trivial to evaluate the responses. One question around alzheimer's is one of my goto questions. I am testing its ability to reason.
There's so much text on this already, it's unlikely to be even engaging any reasoning. Or specifically, if you got a few existing answers from philosophy mashed together, you wouldn't be able to tell it apart from reasoning anyway.