During the project scope planning process, the work breakdown structure should be developed to ______ .

A) the sub-project level
B) the level determined by the project office
C) a level allowing for adequate estimates
D) the cost center level

反刍动物的饲养标准常用（）来表达。

A、每只每天需要量

B、单位饲粮中营养物质含量

C、单位能量中营养物质含量

D、按生产力来表示