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

The main advantage of a Chinese stopper over the one line stopper is that it（）.

A.will not jam on the mooring line

B.is per

C.is easier to use when under heavy tension

D.is safer to use when under heavy tension