A:Where that coat is this?

A:Where that coat is this?B:Is it a black one A:Yes,it is.B:___.A:Here you are.A.I think it's mineB.I think it's his为什么是【B】啊?注意：老师搪塞过去了…… 第一句A的问话，我打错了，应该是A:Whose that coat is this?没有语境，这是一道单选题