The scientists are making further research to develop more advanced rockets________spaceships can be launched.[ ]

A．which   

B．with which

C．/ 

D．with that

在下列页面调度算法中，最容易实现的算法是（）。

A.先进先出算法FIFO

B.最近最久未用置换算法LRU

C.LRU近似算法

D.最佳页面置换算法OPT