--The duty of Project Hope is to help poor children, isn't it?

--Yes, it has built many schools ____ those children can study happily.[ ]

A. where          

B. when          

C. which          

D. what

应税消费品生产企业向购买方收取的（）应并入销售额征收消费税。

A.包装费

B.仓储费

C.优质费

D.延期付款利息