Is that your backpack?　　　　　　. It’s my backpack.A. No they’re not.B. Yes they are

问题补充：

--- Is that your backpack?

--- . It’s my backpack.

A. No, they’re not.

B. Yes, they are.

C. No, it isn’t.

D. Yes, it is.

答案：

A. No, they’re not.

B. Yes, they are.

C. No, it isn’t.

(答案→)D. Yes, it is.

解析：句意：那个是你的背包吗？是的，它是我的。根据后面的It’s my backpack.可知，背包是我的；B项单复数不匹配；故选D。