When the changing of a VHF channel / frequency is accepted，say（）.

A.I am going to change to VHF channel

B.I am certainly going to change to VHF channel

C.Changing to VHF channel

D.VHF channel. has been changed

属于RAM特点的描述是（）。

A.断电后信息消失

B.信息永久保存

C.只能进行读操作

D.字节