单项选择题
A.to avoid mutual interference
B.to keep silence
C.owing to the time-share nature
D.to regulate transmitter power
单项选择题 If EGC receiver shares a same antenna with INMARSAT MES, it means that it can receive MSI（）.
单项选择题 EGC safetyNet transmits（）types of messages for mariners.
单项选择题 However, reception of certain types of MSI messages, such as shore to ship distress alerts and navigational and meteorological warning are（）.