Shari and her family change their use of transportation. They use their private automobile less often, and instead rely more on public transportation, bicycles, and walking. How does their change in behavior affect their ecological footprint? A. The footprint decreases, because the family uses fewer energy resources and reduces their emissions of greenhouse gases. B. The footprint decreases, because the family travels across a smaller area of land. C. The footprint increases, because vehicles such as buses and subways use more energy than a private automobile. D. The footprint is not affected, because the family's use of resources is approximately the same as before.