Consider the following two-period model of dynamically efficient extraction of a non-renewable natural resource. The constant social marginal cost of extraction is 40 in each period and the total stock of the resource is Q = 300 units. Moreover, the social marginal benefit is MB(Qt) = 200 Qt, where Qt is the quantity of resource extracted in period t, for t = 0; 1. The discount factor is 0.8. a) What is the efficient quantity of resource extracted in each period? Provide a graphical representation of the solution. b) What is the marginal user cost (or scarcity rent) of the resource in each period? c) Suppose that there is a market to trade the resource. What is the equilibrium price corresponding to each period? Justify the answer. d) Suppose that it is now expected that because of an extraction technology improvement, while the first period marginal cost of extraction will still remain MXC1 = 40, the second period one will now decrease to MXC2 = 20. Answer the previous questions (a)-(c) under this alternative premise. e) How will the answers to questions (a)-(c) change if, because of new discoveries, the known reserves of the natural resource become Q = 400?