單選題

Mike: My brother has really gone crazy. He says he wants to take up skydiving. Can you believe that? Lily: What? ____________ Mike: I’m not. He’s dead serious. Lily: Well, you have to stop him. It’s really dangerous.

 (A) Am I going crazy?

 (B) I believe he’s dangerous.

 (C) You’ve got to be kidding.

 (D) Have you talked to him seriously?