单项选择题
（）is used for receiving maritime safety information which is automatically printed by the receiver.
A.NAVETEX receiver B.Search and Rescue Transponder C.Emergency Position Indicating Radio Beacon D.Digital selective calling
单项选择题 （）is used for providing homing signals from survival craft for detection by 9Ghzradar.
单项选择题 （）is used for calling and replying,and for transmitting acknowleding and relaying distress alerts.
单项选择题 （）provides a paper trace of course steered by the vessel against time.
