单项选择题
A major advantage of the NAVTEX system when compared to other systems is that（）.
A.the information can be received on an ordinary FM radio B.warnings are printed out for reading when convenient C.broadcasts are at scheduled times D.a low frequency band is used for long distance transmission
单项选择题 A Class S EPIRB is a（）.
单项选择题 A Class C EPIRB（）.
单项选择题 A Class A EPIRB is NOT（）.
