Chinese actor Liao Fan won the Silver Bear for Best Actor at the 64th Berlin International Film Festival, _______ caused a stir in the Chinese film industry.

A．who

B．which

C．what

D．as

某反应器，两种物料按一定比例投入，且原料组分常有波动，则调节系统应选择（）。

A.双闭环比值调节系统

B.单闭环比值调节系统

C.变比值调节系统

D.均匀调节系统