【正确答案】 C

【答案解析】
[听力原文]Questions <15>-<18>
M: Good morning. May I help you?
W: Yes, I want to find out about the bus service between here and my home in Detroit. I came here last week by train, but I think I want to return by bus. I like to try different ways of traveling.
M: I'll try to help you. Here is our schedule. It shows that we have eight buses a day that leave Cleveland for Detroit. I think you'll find that the service is cheaper than the train's.
W: Yes, it looks as though the tickets are quite a bit cheaper than the train tickets. Why is that?
M: The bus trip takes a little longer than the train trip, and we don't have a dining car or a lounge. We do have a rest room, however, and the bus is air-conditioned. The trip should be comfortable.
W: How long is the trip?
M: We have an express bus that takes a little more than three hours, and we have a bus that stops at several cities along the way. It's cheaper, but it takes a little more than four hours. If you don't mind the extra traveling time, it's our best bargain.
W: Can I use my return ticket from the train to pay for my bus ticket?
M: No, you'll have to take that ticket back to the train station. That's different company. They'll give you your money back, and then you can buy a ticket from me here for the bus.
W: Thank you, I want to talk this over with my aunt and uncle before I decide. I appreciate your help.
M: You're welcome.