单项选择题
A man aboard a vessel，signaling by raising and lowering his outstretched arms to each side，is indicating（）.
A.danger，stay away B.all is clear，it is safe to pass C.all is clear，it is safe to approach D.a distress signal
单项选择题 A distress signal（）.
单项选择题 TO EVACUATE A VESSEL FROM CREW AND PASSENGERS FOLLOWING A DISTRESS means（）.
