Cars are safer to drive. Farmers grow more plants. The amount of air pollution is reduced. The number of cars around the world increases.
I gave my students this multiple choice question: A scientist discovered a way to turn plant material into fuel. This more cleanly burning fuel can be used in cars. How do people most likely benefit from turning plant material into fuel?

Only one answer is correct among these 4 choices:
- Cars are safer to drive.
- Farmers grow more plants.
- The amount of air pollution is reduced.
- The number of cars around the world increases.

Could you tell me which one is correct?

The amount of air pollution is reduced.