单项选择题
A.Two licensed GMDSS radio operators
B.Equipment carriage requirements
C.Distress alerting and response
D.All of the above
单项选择题 What are the conditions，under GMDSS，whereby a ship is NOT allowed to depart from any port? （）
单项选择题 VHF Radio is one of the very important navigational instruments on board，（）messages can be sent.
单项选择题 Under the International Code of Signals how are geographical locations such as New York City transmitted?（）