Stations are grouped by countries arranged in the（）order of their country symbols.

单项选择题When engaged on international voyages, ships of 1600 tons gross tonnage and upwards shall be fitted with a（）.

A.radio direction-finding apparatus
B.DSC
C.NAVTEX
D.EPIRB

单项选择题The maritime access code of telephone mode in INMARSAT-A terminal for the AOR(W) is（）.

A.871
B.872
C.873
D.874

单项选择题In Inmarsat-A, “Priority 0” means（）communication.

A.routine
B.distress
C.urgency
D.safety

单项选择题The maritime access code for the IOR is（）in INMARSAT-A Telex Service.

A.581
B.582
C.583
D.584

单项选择题In Inmarsat-A, “Priority 3” means（）communication.

A.routine
B.distress
C.urgency
D.safety