What would most likely occur if the number of cars being driven increased worldwide?

a. more coal would be burned, which would cause the amount of carbon dioxide in the atmosphere to increase.
b. more petroleum would be burned, which would cause the amount of carbon dioxide in the atmosphere to decrease.
c. more coal would be burned, which would cause the amount of carbon dioxide in the atmosphere to decrease.
d. more petroleum would be burned, which would cause the amount of carbon dioxide in the atmosphere to increase.