— What do you think of teaching, John?

— I find it fun and challenging. It is a job ______ you are doing something serious but interesting. [ ]

A. what

B. which

C. where

D. that

单位工程竣工验收的组织和程序中，建设单位应在工程竣工验收( )将验收时间、地点、验收组名单通知该工程的工程质量监督机构。

A．7个工作日前

B．15个工作日前

C．7个工作日后

D．15个工作日后