There are seven questions. Except for the fifth question, the answers of the three people are the same, and other questions have different answers. It can be judged that three people only answered two questions wrong, and the answer to the fifth question is correct.

The remaining six questions, two people have the same answer, and one person has a different answer.

Suppose there is a question, two people answered it wrong and one person answered it right, so let's set it as the first question.

The answers to the second, third, fourth and seventh questions are different, and both of them can only be wrong once, so they are contradictory.

So there is no such thing as two people answering wrong and one answering right.

Therefore, mistakes are only a few.

The correct answer is √×××× √.