从方块中选择适当的句子补全下列对话
A; Hello.                                      B: ________
A:__________                               B: Yes， I am.
A : _________                               B: I’m in Class 6
A : _________                               B: I am twelve.
A: Oh，I am twelve too. ___________           B: Thank you.

A. Please sit on the chair. B. What class are you in ? C. Hello. D. How old are you? E. Are you a new student here?