The maritime radio system consisting of a series of coast stations transmitting coastal warnings is called（）.

A.in an inside passageway
B.in an approved bracket
C.so that it is accessible from the bridge of the vessel
D.so that it will float free if the vessel sinks

A.operates on both military and civilian aircraft distress frequencies
B.transmits both an alerting signal and a homing signal
C.must be the float free type and automatically activated
D.operates with a greater output of signal power

A.for precise navigation in coastal waters
B.by measuring the phase difference of the dots and dashes
C.as an aid to ocean navigation
D.if the vessel is fitted with a special Consol receiver