Suppose that both the price of gasoline and the amount of gasoline sold decline. Which of the following would account for this?
a. a shift left of the demand curve, but no change in the supply curve
b. a shift right of the demand curve, but no change in the supply curve
c. a shift left of the supply curve, but no change in the demand curve
d. a shift right of the supply curve, but no change in the demand curve