When a tax on gasoline and a rebate program of equal amount is implemented like the one in your test

a. the tax restricts gas usage and the rebate program increases usage, but the net effect is an increase in consumption.

b. the tax restricts gas usage and the rebate program restricts usage further.

c. any of the above can occur depending on the size of the tax.

d. the tax restricts gas usage and the rebate program encourages usage, but the net effect is a decrease in consumption.