【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