One method of reducing the length of radio transmissions without distorting the meaning of your words is by using（）.

单项选择题On which vessels is GMDSS required? （）

A.All vessels capable of international voyages
B.Vessels operating outside of the range of VHF coastal radio stations
C.SOLAS Convention ships of 300 gross tonnage or more
D.Coastal vessels of less than 300 gross tons

单项选择题If your vessel is equipped with a radiotelephone，what must also be aboard?（）

A.Certificate of Inspection
B.List of ship stations
C.Copy of ship to shore channels
D.Radio station license

单项选择题If a GMDSS radio operator initiates a DSC distress transmission but does not insert a message，what happens? （）

A.The transmission is aborted and an alarm sounds to indicate this data must be provided by the operator
B.The transmission is not initiated and "ERROR" is indicated on the display readout
C.The transmission will be made with "default" information provided automatically
D.The receiving station will poll the DSC unit of the vessel in distress to download the necessary information

单项选择题I have no choice（）to put such remarks.

A.or
B.and
C.but
D.unless

单项选择题I have altered course to 245 degrees for（）.

A.identify
B.identifier
C.identity
D.identification