Logical multiple choice questions

Classification analysis, assuming (1) that someone bought Mongolian knives correctly, because there can only be one pair, then (2) those who didn't buy them can only be wrong, which means that they all bought them, and (3) they must be wrong. If (3) is wrong, it means that Wang and Zhang didn't buy it, and (2) and (3) are contradictory, it means that the hypothesis is (65438).

Assuming that (3) is correct, then (1) must be correct, because there can only be one correct one, so it doesn't meet the question.

So it can only be (2) correct, (1)(3) wrong, that is.

(2) If it is right, some people don't buy knives; (1) If it is wrong, no one will buy a knife; (3) If it is wrong, Zhang Wang won't buy a knife.

So I came to the conclusion that only A didn't buy a knife.