Task: Dialogue Generation
Input (English): M: Mary, I'm going to London tomorrow. ,F: Oh, yes. Are you going by bus? ,M: It's the best way. There is a fast train but it's too expensive for me.
(A) F: So, you will travel to London by car because there is no fast train? (B) F: OK, I see. You mean there is a fast train and it's too cheap for you, so you will travel to London by train. (C) F: OK, I see. Since it's too expensive for you, you will travel to London by bus the day after tomorrow. (D) F: I’m sorry, I don’t understand. Could you say it again?
Output (English): D