On small passenger vessels, all spaces containing gasoline-powered machinery or gasoline storage tanks must be ventilated with __________.

Correct Answer: Option A — natural air supply and mechanical exhaust fans

46 CFR 182.460 mandates that spaces containing gasoline machinery must have natural supply ventilation and mechanical exhaust. This combination ensures that heavier-than-air gasoline vapors are effectively removed from the bilge, preventing the accumulation of explosive mixtures in enclosed machinery spaces.