单项选择题
Which condition represents the appropriate time for setting off distress flares and rockets? （）
A.Only when there is a chance of their being seen by rescue vessels B.At half hour intervals C.At one hour intervals D.Immediately upon abandoning the vessel
单项选择题 Which categories of NAVTEX messages may not be selectively rejected through receiver programming?（）
单项选择题 Which action should you take after sending a false distress alert on VHF?（）
单项选择题 When you are firing a pyrotechnic distress signal，it should be aimed at（）.
