用所给句子完成对话，有一项多余。从所给的选项中选出最佳选项。

A: Hello, Mike! What's the time?

B:

A: Where is Bob? I can't find him.

B: I don't think he can come.

A:

B: He has to look after his sister.

A:

B: She doesn't feel well.

A: Did she go to see the doctor?

B: Yes.

A:

B: The doctor said nothing serious, but she has to rest.

A. Why can't he come? B. I'm sorry to hear that. C. Where did the doctor go? D. It's half past eight. E. What did the doctor say? F. What's wrong with his sister?