carpool to school ride a bus to school ride a bike to school drive alone to school
I gave my students this multiple choice question: Cars are powered by gasoline made from oil. Which is the best way to conserve gasoline?

Only one answer is correct among these 4 choices:
- carpool to school
- ride a bus to school
- ride a bike to school
- drive alone to school

Could you tell me which one is correct?

ride a bike to school