M: Is that Jack's mother over there? ,F: No, it can't be her. She's traveling with Jack in Canada. That must be his mother's twin sister.
(A) M: Jack's mother is traveling with Tom in Japan. (B) M: So she must be Jack's aunt. (C) M: Jack's sister is traveling with Jack in China now. (D) M: I am sorry. You spoke so rapidly that I did not catch the meaning of what you said. Could you repeat that?
B