【单选题】
PAN-PAN repeated three times over the radiotelephone indicates which type of message will follow?()
A、Distress
B、Safety
C、All clear
D、Urgency
A、Distress
B、Safety
C、All clear
D、Urgency
A、A.securite repeated 3 times B、B.safety repeated 3 times C、C.pan pan repeated 3 times D、D.securite securite repeated 3 times