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

A．which   

B．with which

C．/ 

D．with that

有关汇兑业务的止付/解止付描述正确的有（）.

A.当汇兑机构内部发现汇款有疑问时，可经授权止付汇款

B.当汇兑机构内部发现汇款有疑问时，可无须授权止付汇款

C.解止付须由原止付机构办理

D.解止付无须由原止付机构办理