On board small passenger vessels, fittings used in a gasoline supply line must be __________.

Correct Answer: Option D — made of non-ferrous metal, and be a flare or non-bite flareless type

46 CFR requires gasoline fuel system fittings to be constructed of non-ferrous metal to prevent corrosion and sparking. Flare or non-bite flareless types are mandated to ensure a secure, vibration-resistant, and leak-proof connection, which is critical for preventing fuel spills and subsequent fire hazards in machinery spaces.