收益递增递减原理可以帮助我们确定( )。

A．最佳用途和最佳规模

B．最佳集约度

C．最佳规模和最佳集约度

D．最佳用途

The commander of a rescue unit designated to co-ordinate search and rescue operations within a specified area is the（）.

A.General commander

B.Commander general

C.Search commander

D.On-scene commander