Soon children in the camp had many new friends,         they shared food, stories and projects.[ ]

A. for which        

B. with whom        

C. of which        

D. to whom

在系统开发方法论的实际发展过程中，共有两种开发方法被提倡和发展，它们是 ( )和自顶而下的开发方法。

A．自上而下

B．全面进行

C．自底而上

D．单纯规划