The survivors of the crashed plane had no food or water and were ________ the extreme cold weather.[ ]

A. in the possession of  

B. in the charge of

C. at the mercy of  

D. at the risk of

目前常用项目管理软件有( )。

A．综合进度计划管理软件

B．合同事务管理软件

C．费用控制管理软件

D．综合进度控制管理软件和合同及费用控制管理软件