单项选择题
A Class C EPIRB（）.
A.is primarily designed for vessels operating up to 50 miles offshore or on foreign waters B.transmits a signal that can be detected by satellite C.must be manually activated D.operates in the medium and low frequency bands
单项选择题 A Class A EPIRB is NOT（）.
单项选择题 A check line is（）.
单项选择题 （）is the course to reach you?
