A、They are paying for his education. B、They invited him to their party. C、They took him on a vacation with them. D、They let him

W: David! Can I give you a hand with one of those grocery bags?
M: Sure, Nancy! Could you take this one, please? I didn’t realize how heavy these bags would be.
W:Why did you buy so much stuff when you have to walk home from the store?
M:Well, I didn’t intend to buy a lot—but I’m having some people over and I guess I needed more than I expected.
W: What’s the occasion?
M:The people I live with, the Kramers, have been on vacation for a month and I thought I’d surprise them. I’m inviting some of their friends and family for a welcome-home dinner.
W: That’s really thoughtful of you.
M:I figure it’s the least I can do for them. They’ve been letting me stay with them rent-free while I’m in school.
W: Really? That’s pretty generous of them.
M:Well, they understand how difficult it is to make ends meet when you’re a student. They’ve been such a big help to me, I thought that this might be a small way to thank them for their generosity.
1. What is David trying to do?
2. Why did David think he wouldn’t have a problem?
3. Why is David appreciative of the Kramers?