It was a pity that when we hurried to the lecture hall, the lecture_________, so we heard only the end and missed most part of it.

A．was finishing

B．has just finished

C．just finished

D．had just finished

某建设项目总投资为3500万元，估计以后每年的平均净收益为500万元，则该项目的静态回收期为（）年。