When testing a Class A EPIRB you will know
题型：单项选择题
问题：
When testing a Class A EPIRB you will know the EPIRB is working properly if you hear on 99.5 Mhz FM or any vacant frequency on a nearby AM radio（）.
A.a distinctive signal
B.the Morse Code signal for SOS
C.a computerized voice announcement of Mayday
D.your vessel's International Radio Call Sign
