A、  B、  C、  B本句为询问项目截止日期是否应该延长的助动词(Should)疑问句。

Why was Francis sent to Germany last week?
(A) Ten cents per call.
(B) That’s a weak excuse.
(C) He attended a conference.

Should we extend the project deadline?
(A) The projector is in my office.
(B) I suggest we do.
(C) On the schedule.