单项选择题
A.forty two months from the date of manufacture
B.thirty six months from the date of the last inspection
C.twenty four months from the date of approval
D.twelve months from the date of purchase
单项选择题 The radiotelegraph alarm signal may be used to announce（）.
单项选择题 The distress message of a ship should include considerable information which might facilitate the rescue. This information should（）.
单项选择题 The color of rockets，shells，or rocket parachute flares used to indicate that the vessel is in distress and requires immediate assistance is（）.