Refer to the graph below to answer these questions about twoperiod extraction model below. The graph shows the choice between mining phosphate in period 1 versus in period 2. Assume all of the phosphate must be extracted by the end of period 2. NMBl = net marginal benet, year 1; NM I32 = net marginal benet, year 2; PVINMBZ} = present value of net marginal benet, year 2 NMBI \"\"132 NMBJ Pvmmaz) I Quantity extracted a. Explain why the allocation of phosphate [Q] between period 1 and period 2 is not split evenly. b. Suppose the discount rate rises. Carefully explain in words how this would change the graph. c, If the discount rate rises, will the allocation between period 1 and period 2 change? If so, how? Give an intuitive [ie., explain your reasoning with words, not the graph} explanation for your