A.all vesselsB.selected groups of shipsC.a particular s……

单项选择题DSC distress relays can be transmitted by either（）or（）.

A.a coast station/a ship station
B.an EPIRB/a SART
C.ARQ/FEC
D.a back-up satellite/a land SAR unit

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.

A.SES/DSC/EPIRB
B.SART/radiotelephone
C.COSPAS-SARSAT
D.both B and C

单项选择题Mariners can use DSC for（）.

A.general communication
B.distress alerting and safety calling
C.receive MSI
D.both B and C

单项选择题Equipment requirement vary according to（）.

A.Ship owner‟s will
B.economic condition
C.the area in which the ship operates
D.different orders of all countries