A、The tickets are only available on unpopular times. B、They want people to travel when trains are not normally full. C、They want

W: Well, did you get to find out about tile trains?
M: Yes, I’ve got the leaflets here. And you got the coaches ,did you?
W: Yes, look, I’ve just worked it out.
M: Well, that’s OK. There are trains all day, according to this. Here, there’s one leaving King Cross at 8:00 in the morning.
W:  Oh, goodness no. That would mean getting up at 6: 00. Count me out for that one, when’s the next?
M: 10 o’clock. Leaves Kings Cross at 10 o’clock, gets into Aberdeen at 17: 21. Not bad. Seven hours and a bit on the way. It’s 530 miles, after all.
W: I suppose it’s very expensive, isn’t it?
M: No,  what about going by plane?
W: You know how I feel about flying.
M: What about the coaches?  But can you imagine being stuck in a bus for twelve hours? At least on the train you can get up and walk about a bit, you know, stretch your legs.
W: All right, then, you do better. Find me a nice cheap night train.
M: That’s the trouble. There aren’t any cheap tickets at night. It says so clearly here. It says the cheap tickets are valid only for trains timed to depart between 10 o’clock in the morning and 2:00 in the afternoon. Mum, here it is, not valid for sleepers.
W:  That’s why the Day, Savers are cheap, you see. They want people to travel at unpopular times.