The difference between a class A and a cla
题型：单项选择题
问题：
The difference between a class A and a class B EPIRB is that the class A EPIRB（）.
A.operates on both military and civilian aircraft distress frequencies
B.transmits both an alerting signal and a homing signal
C.must be the float free type and automatically activated
D.operates with a greater output of signal power