||A small country can import a good at a world price of 10 per unit. The domestic supply curve of the good is S = 20 + 10P The demand curve is D = 400 – 5P In addition, each unit of production yields a marginal social benefit of 10. a. Calculate the total effect on welfare of a tariff of 5 per unit levied on imports. b. Calculate the total effect of a production subsidy of 5 per unit. c. Why does the production subsidy produce a greater gain in welfare than the tariff? d. What would the optimal production subsidy be?