Answer:
-wind is the correct answer.
Step-by-step explanation:
Wind energy is a renewable source of energy and it is nonpolluting.
Wind resources are a renewable source of energy and it is nonpolluting doesn't contaminate the air whereas Coal, oil, gasoline emits particulate matter, sulfur dioxide, nitrogen oxides that affect human health and cause environmental damages.
-wind resource produces the cleanest energy because Wind energy does affect the environment as it does not cause pollution and it does not emit harmful gases that are the reason wind energy is the cleanest energy resource whereas Coal, Gasoline, and Oil are the polluting source affect the environment.