Answer:
B. gasoline combustion
Step-by-step explanation:
Smog is a term that refers to a combination of smoke and fog. It describes intense air pollution that blackens the atmosphere with a fog-like cloud. The major contributors of smog factories, power plants, and automobile exhaust. From the list provided, gasoline combustion contributes most to the formation of smog. These are car exhausts, heavy machine emissions, and other equipment fueled by petrol or diesel.