单项选择题
A station in the mobile service the emissions of which are intended to facilitate search and rescue operations is（）.
A.EPIRB B.SART C.Mobile Station D.Distress Alerting
单项选择题 （）process the distress signal from EPIRB to determine its position and identity.
单项选择题 The range of a MF coast station is normally（）nm.
单项选择题 Exchange of answer-backs acts a confirmation that the messages（）at the destination.
