原发性腹膜炎和继发性腹膜炎的区别主要在于（）

A.腹痛性质

B.腹胀程度

C.病原菌种类

D.体温升高程度

E.有无腹腔原发病灶

Which action should be taken on receipt of a GMDSS distress alert（）.

A.Read the display screen and/or printout

B.Silence the alarm

C.Listen for any follow up voice/telex transmission on the appropriate frequency

D.All of the above