is often deliberately tricky

Then you're not really guessing at the truth of the statement. Instead you're guessing at the state of mind of the examiner, which involves a very different set of heuristics and biases.

Keep doing that and you may end up thinking, "maybe the correct answer is that he didn't defeat him because it was a Pyrrhic victory? Maybe Bosworth is spelled wrong? Maybe there's a dispute over the right year due to difficulties inherent in dating medieval events?"