—Did you enjoy yourself yesterday?

—Yes. As you saw, party went on in _______ most pleasant atmosphere.

A．the; a

B．the; the

C．a; the

D．a; a

保安员在执行勤务时，是依据（）完成勤务任务。

A.保安服务合同

B.保安勤务方案

C.客户单位要求

D.保安公司要求