从所给出的句子中选出合适的完成对话。

A. You like helping people.    B. This is Peter.    C. Do you want to go with us? D. Have a good day!    E. I usually go to the Old People's Home on Saturday.

Peter: Hi, Joe!

Joe: Hello, Peter.

Peter: Do you want to go to the park with me this Saturday?

Joe: I am sorry. .

Peter: What do you do there?

Joe: We clean the rooms for the old people. We also talk and sing songs with them.

Peter: . That's great.

Joe: Thank you.

Peter: I really want to, but I have to go to the park with my grandparents.

Joe: Oh, it doesn't matter.

Peter: You too.