I promised to get there before 5 o’clock, but now the rain is pouring down. They ______ for me impatiently.

A．may wait

B．ought to wait

C．could wait

D．must be waiting

应收账款质押登记公示系统的常用户可以是（）。

A.金融机构

B.企业

C.个人

D.事业单位