⦁ What are the main sources of traffic noise in the city?
⦁ ( ) They are the motors and exhaust system of planes, bigger trucks, buses and bikes.
⦁ ( ) They are the motors and exhaust system of autos, smaller trucks, buses and motorcycles.
⦁ ( ) They are the motors and exhaust system of autos, bigger trucks, planes and motorcycles.
⦁ ( ) They are the motors and exhaust system of planes, smaller trucks, bikes and motorcycles.