单项选择题
（）process the distress signal from EPIRB to determine its position and identity.
A.COSPAS-SARSAT B.ground receiving stations C.storing distress signal D.Near polar orbiting satellites
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.
单项选择题 The beacon located on board aircraft is termed（）.
