Alternative fuels are at every gas station. Gasoline comes from a limited resource. Alternative fuels cause pollution. Gasoline engines are too expensive to make.
I gave my students this multiple choice question: Why are alternative fuels being used in some automobiles?

Only one answer is correct among these 4 choices:
- Alternative fuels are at every gas station.
- Gasoline comes from a limited resource.
- Alternative fuels cause pollution.
- Gasoline engines are too expensive to make.

Could you tell me which one is correct?

Gasoline comes from a limited resource.