单项选择题
How long must the GMDSS radio log be retained on board（）.
A.At least two years after the last entry B.At least one year after the last entry C.At least 90 days after the last entry D.At least 30 days after the last entry
单项选择题 Each satellite broadcasts（）traffic on a designated channel.
单项选择题 At sea，all required GMDSS equipment（other than survival craft equipment）must be proven operational by（）.
单项选择题 （） operates at a transfer rate of up to 9600 bits per second and is telephone，telex and facsimile（fax）capable.
