While testing a cargo tank，your oxygen indicator reads 25% oxygen in the tank. You would then （）.

单项选择题Which vessel in ocean service is not subject to Annex V of MARPOL 73 78? （）

A.A 20-foot sailing vessel
B.A 26-foot tug and tow
C.An uninspected 35-foot passenger vessel
D.A Navy Destroyer

单项选择题Which substance is NOT considered to be Oil under the pollution prevention regulations? （）

A.Petroleum and fuel oil
B.Sludge
C.Oil mixed with dredge spoil
D.Oil refuse and oil mixed with wastes

单项选择题Which step is NOT generally taken when gas-freeing a tank?（）.

A.Washing the tank interior with sea water
B.Application of degreasing solvents
C.Removal of corrosion products and sludge
D.Fresh air ventilation

单项选择题Which statement is TRUE concerning the ventilation of engine and fuel tank compartments on uninspected towing vessels using fuel with a flash point of 100°F?（）

A.There shall be at least 3 ventilator ducts open to the atmosphere
B.At least one exhaust duct shall extend from the open atmosphere to the lower portion of the bilge
C.At least one intake duct shall extend from the open atmosphere to the lower portion of the bilge
D.Only vessels using fuel with a flash point above 110°F need ventilate engine and fuel compartments

单项选择题Which statement is TRUE concerning protection of double bottom tanks against excessive pressure? （）

A.Each vent for the tank must be equal to the area of the tank filling line
B.The tanks must be protected by overflows
C.The total area of the vents or the overflow shall be at least equal to the area of the fill line
D.There must be twice as much vent area as the area of the fill line