—Do you know _________ the meeting?

—Tomorrow morning.

A．when they had

B．when they are going to have

C．when did they have

D．when are they going to have

下述哪项最有助于鉴别细菌性痢疾和溃疡性结肠炎（）

A.有无里急后重

B.有无脓血便

C.有无便血

D.抗生素治疗是否有效

E.有无发热