单项选择题
A.they can be used by mariners who do not know Morse code
B.only an ordinary FM radio is necessary to receive these warnings
C.information on a given topic is only broadcast at specified times
D.they cover a broad spectrum of the radio band allowing reception on almost any type of receiver
单项选择题 The Master shall insure that the Emergency Position Indicating Radiobeacon (EPIRB) is（）.
单项选择题 The maritime radio system consisting of a series of coast stations transmitting coastal warnings is called（）.
单项选择题 The Emergency Position Indicating Radiobeacon on a cargo vessel must be stowed（）.