With the nuclear crisis worsening in Iran, the world's attention is fixed again on   is called the Middle East. [ ]

A. which        

B. that        

C. what      

D. it

共享硬盘服务器将共享硬盘空间划分为多个虚拟盘体，虚拟盘体分专用盘体、( )、( )3部分。