单项选择题
The Class A EPIRB transmits a signal（）.
A.that follows the curvature of the earth B.that can be picked up by SARSAT satellite C.that activates an alarm on board nearby aircraft D.to alert shore stations and then transmits a homing signal
单项选择题 Survival craft EPIRBs (Class S) are（）.
单项选择题 Proper GMDSS watchkeeping includes（）.
