单项选择题
Which statement is TRUE（）.
A.Key letters or abbreviations may not be used in GMDSS radio logbooks under any circumstance B.Urgent communications do not need to be entered in the GMDSS radio log C.Both of the above D.None of the above
单项选择题 Which statement is TRUE（）.
单项选择题 Which statement is generally correct regarding the maintenance requirements for ships under GMDSS（）.
单项选择题 Which statement concerning reserve sources of energy for GMDSS is FALSE（）.
