A.a mother shipB.a lifeboatC.a life craftD.all of A,B,C……

单项选择题All stations which receive a distress alert shall immediately cease（）.

A.any transmission
B.any harmful transmission
C.to use radiotelephone
D.using radiotelephone

单项选择题When receiving a distress alert, the SAR authorities ashore and the ships in the vicinity of the ship in distress will（）soonest.

A.reach the distress area
B.conduct a sector search
C.send rescue vessels
D.assist coordinately in SAR operation

单项选择题In the GMDSS, distress alerting can be transmitted in（）directions.

A.1
B.2
C.3
D.4

单项选择题We（）the distress signal on our own radio before the shore station relayed it to us.

A.received alreadly
B.have received
C.had received
D.was receiving

单项选择题The frequency 156.525MHZ and 156.8MHZ should be used in the band of（）.

A.MF
B.VHF
C.HF
D.LF