What is the minimum number of deck officers，able seaman or certificated persons required for a lifeboat on a vessel in ocean service?（）

A.Six by seven galvanized wire rope
B.Six by twenty-four improved plow steel wire rope
C.Six by thirty-seven preformed fiber-core wire rope
D.Six by nineteen regular-lay filler wire rope

A.Each lifeboat must have a launching appliance
B.Launching appliances must be of the gravity type
C.There may not be more than two launching appliances on the same deck
D.All of the above

A.Moisture accumulation in winch motor damaging the electrical wiring
B.Freezing of gears in cold weather
C.Corroding of sheaves on the davits so they will not rotate
D.All of the above