Okay, the obvious questions are things like, "is this person a male" - since it's yes or no we can't give multiple options, which sucks. But, uh, that and like, are they over twenty, but that still leaves a lot of narrowing down. There's one thing, looking at the people on the list... if we ask, "do they have amnesia?" it'll either cut it down at lot, or just eliminate a small group.