单项选择题
Distress traffic（）all messages relating to the immediate assistance required by the ship in distress, including search and rescue communications and signals for locating.
A.consists of B.is consisted of C.consisted of D.are consisted of
单项选择题 The transmission of a（）indicates that a ship is in distress and requires immediate assistance.
单项选择题 The GMDSS is composed of（）.
单项选择题 MSI is broadcast via（）.
