根据下面的对话内容，从对话前的选项中选出最佳选项填入空白处，将代号填入空白处。选项中有一个多余选项。

A. And I think e-mail is one of the best ways to communicate with others. B. I’ve got so many e-mails to go through. C. I agree with you. D. Of course! E. How many e-mail addresses have you had? F. I feel like getting more e-mails.

A: It’s very late. Are you still on the computer?
B: Well, yes. （1）    
A: What kind of e-mails?
B: Some are messages from my friends and some are from the relatives.
A: Do you have to write them back right away?
B:（2）    Usually people want a quick reply.
A:（3）   
B: I’ve already had 40 people’s addresses in my address book!（4）    
A:（5）    E-mail is really very convenient(方便的).