If the fact is
Nancy is a cat, Mancy is a dog.
and I asked a question
Is Nancy a cat?"
Suppose someone else answers
Yes, Nancy is a cat while Mancy is an octopus.
It correctly answers the question but somehow mentions something wrong, I feel strange to accept it, but writing myself a new answer also seems a bit strange, as the "Nancy is a cat" part is just a complete copy of his.
What should I do in this situation? Write a comment below the answer and waiting for the answerer to fix so I could accept?