All of the questions are included in the screenshot attached

QUESTION 1 A new study demonstrates that wind farms produce positive externalities for farmlands in the form of increased crop yield. Suppose the private marginal benefits (marginal revenues) from wind can be explained by the function PMB(q) = 50 - 0.5q and the private marginal cost are PMC(q) = 5 + 0.1q. At a marginal external benefit of 6 per unit, what is total surplus under an optimal Pigouvian subsidy? 2167.5 1687.5 1687.5 1912.5 QUESTION 2 A new study demonstrates that wind farms produce positive externalities for farmlands in the form of increased crop yield. Suppose the private marginal benefits (marginal revenues) from wind can be explained by the function PMB(q) = 50 - 0.5q and the private marginal cost are PMC(q) = 5 +0.1q. At a marginal external benefit of 6 per unit, what is the total surplus at the privately optimal equilibrium? 1657.5 1687.5 2137.5 1882.5 QUESTION 3 Take the following demand function: q (p) = 80 - 4p. What is the marginal revenue function under a monopolist firm? MR = 80 - 4q MR = 20 - 0.25q MR = 20 - 0.5q MR = 20 - 0.75