根据对话内容，运用方框中所给的句子选项补全对话。选项中有一项是多余的。

A：Hey, Frank. I need your help.

B：What, Mom?

A：Your aunt left (落下) her keys in our house.

B：Yes, Mom. Oh, four keys are on the sofa.

A：No, they aren't. Your aunt only has three keys.

B：I see. Oh, some keys are under the sofa, Mom.

A：Let me have a look! Great! They're your aunt's. Thank you for your help, my dear son.

B：

A. You're welcome. B. Are they my aunt's? C. I think they are on the table. D. The four keys are your father's. E. It's a key ring (钥匙环) with three keys. F. Can you help me find them?