W: Look! Is that Tom over there, the boy reading a book? M: That can't be Tom. That must be his brother Jim. W: Why? M: Because Tom flew to Beijing just last night. He couldn't have returned yet., Question: What are the speakers mainly talking about? (A) When Jim will return. (B) When Tom flew to Beijing. (C) Who is reading a book there.
(C) Who is reading a book there.