On a small passenger vessel, backfire flame arrestors are installed on a/an __________.

Correct Answer: Option A — gasoline powered engine

Backfire flame arrestors are required on gasoline-powered engines to prevent ignition of fuel vapors in the engine compartment. Gasoline engines utilize carburetors or throttle bodies where a backfire could ignite flammable vapors; diesel engines, which rely on compression ignition, do not present this specific risk to the intake system.