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Can someone please explain question 11 in the first LR section of PT 65 to me? Though I can understand why the other answers are incorrect, I don't like the correct one either.

The flaw I read in the initial argument is the assumption that one possible conclusion is the only conclusion. The correct answer, however, seems to assert not a conclusion, but an assumption that something (which almost seems potentially correlated - that everyone ate something from the camp cafeteria that made them sick) may be eliminated as a potential conclusion.

I mean, I can kind of convince myself that they're both the same sort of flaw and the answer is just flipped (asserting one piece of "evidence" leads to a falsely confident conclusion or elimination of a possibility), but that doesn't make me feel reassured that I'd catch on to something like this in the future.

Break this down for me, please?

The flaw in the argument is that the only finger prints were mr t therefore who ever stole the diamond wore gloves and didn't leave prints. But it's assuming that mr t didn't steal it and therefore if he did he left finger prints and did not wear gloves.

Answer a has the same flaw the argument is assuming the food didn't cause the kids to get sick