For a small country called Treetopia, the equation of the domestic demand curve for paper is QD = 210 2P, where QD represents the domestic quantity of paper demanded, in tons, and P represents the price of a ton of paper. For Treetopia, the equation of the domestic supply curve for paper is QS = -90 + 3P, where QS represents the domestic quantity of paper supplied, in tons, and P again represents the price of a ton of paper. Refer to Scenario 9-1. If Treetopia prohibits international trade in paper, then the equilibrium price of a ton of paper is a. $60 and the equilibrium quantity of paper is 90 tons. b. $64 and the equilibrium quantity of paper is 82 tons. c. $40 and the equilibrium quantity of paper is 130 tons. d. $52 and the equilibrium quantity of paper is 106 tons