Fixed carbon dioxide fire extinguishing systems shall be installed to protect enclosed machinery and fuel tank spaces of all vessels using gasoline or other fuel having a flash point of __________. (small passenger vessel regulations)

Correct Answer: Option D — 110°F or lower

46 CFR 181.400 mandates fixed fire extinguishing systems for machinery spaces on small passenger vessels using fuel with a flash point of 110°F or lower. This regulation ensures adequate fire suppression for volatile fuels, mitigating the high risk of explosion or fire in enclosed engine and tank compartments.