【正确答案】 C

【答案解析】[听力原文]
   W: Do you think families have changed much in the last 50 years?
   M: I think families everywhere have changed a lot in the last five decades.
   W: What do you think is the biggest change?
   M: Well, in the past, three or four generations would live together under the same roof. Nowadays, relatives living in the same city have become rare.
   W: That's true. You know, some husbands and wives don't even live in the same city any more.
   M: Would you ever consider having your parents live with you when they get older?
   W: I guess I'm a bit old-fashioned. I'd rather have my parents live with me than live in a retirement home.
   M: That's very respectable, but I could never live with my parents. I usually only see them at our Christmas celebration and that's enough!
   W: How about your other siblings? Do they spend a lot of time with your parents?
   M: Two of my sisters still live at home, even though they have already graduated from university and had jobs. They enjoy spending their free time with my parents. I guess in that respect, I'm the black sheep of the family.
   W: I see. Do your parents ever ask you to come home to visit them more often?
   M: They're always asking me to come home, but I think our relationship is better if we keep a distance from each other. Whenever we see each other, all we do is fight.
   W: Well, you know what they say, "You can choose your friends, but not your family."
   What does the man think is the biggest change for families?