Fossil Fuel Combustion from Millions of Cars Contributes to Air

Multiple Choice

Fossil fuel combustion from millions of cars contributes to air pollution and climate change. Given this information, which is the best example of sustainability in transportation?

A) driving yourself to class early in order to get a good seat
B) carpooling with friends to a weekend camping trip
C) taking the city bus across town to get groceries
D) walking to work in order to avoid traffic congestion