As a project manager, you examine project results over time to determine how project is performing over time. This can be done through ______ .

A) performance reviews
B) variance analysis
C) trend analysis
D) earned value management

党的干部是党的事业的（），是人民的公仆，要做到忠诚干净担当。

A.中心

B.重心

C.骨干

D.主人