—Please give this note to John.

—OK, I'll give it to him as soon as he _________.

[ ]

A. is coming back

B. will come back

C. comes back

SCADA系统采用很多措施确保系统和管线的安全，其中包括（）。

A.异常情况设置报警功能

B.联锁保护功能

C.关键设备采用冗余配置

D.UPS进行供电