【单选题】What. action should a GMDSS radio operator take when SafetyNET distress or urgency messages are received by the vessel's EGC receiver?
A.
No immediate action is required.
B.
Aural and visual alarms are activated, and require manual deact.ivation.
C.
Transmission of acknowledgement should be achieved imm_ediately.
D.
Reset the EGC receiver imnediately.