单项选择题
On-scene communications will normally take place between（）.
A.ship in distress and assisting units B.NCS and RCC C.RCCs and „0n-scene commander‟ or “co-ordinator surface search” D.ship in distress and coast station
单项选择题 （）are used for distress alerting as a rule.
单项选择题 Mariners can use DSC for（）.
单项选择题 Equipment requirement vary according to（）.
