Which statement is TRUE（）.

A.GMDSS radio logs are required to contain entries pertaining to all incidents connected to radio communication service which appear to be of importance to the safety of life at sea
B.All distress communications must be entered in the GMDSS radio log
C.Both of the above
D.None of the above

A.Redundancy of functions of certain equipment will partially meet this requirement
B.On-board maintenance provided by a person holding a GMDSS maintainer's license will partially meet the requirements
C.Shoreside maintenance and scheduled tests and inspections will partially meet this requirement
D.All of the above

A.While the ship is at sea，there must be available at all times a supply of electrical energy sufficient to operate the radio installations and to charge any batteries used as part of a reserve source of energy
B.Both the VHF and MF/HF installations must be simultaneously supplied
C.A means of ensuring a continuous supply of electrical power must be provided to all GMDSS equipment that could be affected by an interruption in power
D.If a UPS or equivalent is used to supply power to the ship's GPS receiver or other source of positional information，a means must be provided to ensure the continuous supply of the information in the event of a failure to the ship's main or emergency source of power