Which system expels burned gases to the rear and reduces engine combustion noise?

Answer: D — Exhaust System

Exhaust systems are responsible for removing the burned gases from the engine and quieting the exhaust sounds. After combustion, the hot gases travel from the exhaust manifold into the exhaust pipe, often through a catalytic converter, then through a muffler that uses chambers and perforated tubes to dampen sound, and finally exit out the tailpipe toward the rear of the vehicle. Routing the exhaust to the rear helps keep fumes away from the cab, while the muffler specifically reduces engine noise. Other components like the radiator cool the engine, overhead hatches relate to ventilation or access, and an air compressor provides compressed air for braking or tools, not for expelling exhaust or reducing noise.