The diagram shows the demand and the supply curves for a second-hand textbook. The curves intersect at (Q, P) =
(24, 8). Which of the following is correct?
a. There is no equilibrium price and quantity in the market of second-hand goods.
b. If the price is 5, the sellers have an incentive to lower the price in order to sell more.
c. If the price is 9, there is excess supply.
d. The equilibrium quantity is 8.
e. In total, 40 books will be purchased in the market.