单项选择题
Which Inmarsat system applies store-and-forward messaging?（）
A.Inmarsat-A B.Inmarsat-B C.Inmarsat-C D.Inmarsat-F
单项选择题 The basic concept of GMDSS is（）.
单项选择题 SOLAS vessels should be able to communicate with a shore station（）.
单项选择题 General radio communications in the global system may（）ship’s safety.
