听力原文：M: The summer holiday is coming, but I really don't know what to do. There doesn't seem to be any jobs available.
W: Why. don't you try house-sitting？ Last summer Cindy was a house sitter for the Smiths when they went away on vacation. They hired Cindy to stay. in their house because they didn't want it left empty.
M: You mean they paid Cindy just to live in their house？
W: It wasn't that easy. She had to water the house plants, mow the lawn, and even take care of the pets.
M: I guess it is a little like baby-sitting, except you're taking care of a house instead of children.
W: The student employment office still has a few jobs posted.
M: Do I just have to fill out an application？
W: You have to have an interview with the homeowner and provide three references at least.
M: That seems like a lot of trouble for a summer job.
W: Well, the homeowner wants some guarantee that they can trust the house sitter. You know they want to make sure you're not the type who'll hold wild parties in their house, or bring a group of friends in with you.
M: I see. House sitters who do that sort of thing probably aren't paid then.
W: Usually they're paid anyway just because the homeowners don't want to make a fuss. But if the homeowner reports it, the house sitter won't be able to get another job easily. So why don't you apply？
M: I think I will. Thank you.
(20)

A. They left their pets with neighbors.
B. They rented their house to a student.
C. They hired someone to stay in their home.
D. They asked their gardener to watch their house.