—How nice the building is! What is it used for?

—It             as a hotel. But I'm not sure. [ ]

A. must be used

B. is used

C. may be used

D. is using

开瓣音是由于（）

A．肝硬化腹水 

B．急性胃穿孔致腹膜炎 

C．胰腺囊肿 

D．癌症晚期恶病质 

E．腹白线疝