Coal, oil, and natural gas

A.

are renewable natural resources.

B.

are in very short supply for consumers.

C.

release carbon dioxide when they are burned.

D.

are clean fuels that contribute little to pollution.

Coal, oil, and natural gas C) release carbon dioxide when they are burned. They are non-renewable resources, but they are in large supply to consumers, and they are also NOT clean fuels and contribute greatly to pollution.