Rock-climbing is a breathtaking activity, very popular nationwide among young people, ______ cooperation as well as courage plays an important role.

A．who

B．where

C．which

D．of which

通过工程建设形成的工程项目的质量，应满足用户从事生产、生活所需的功能和使用价值，符合设计要求和( )。

A．质量评定标准

B．规范规定的标准

C．合同规定的质量标准

D．环境协调性的要求