Question 20. 2 industries emit greenhouse gases (GHG): Energy (E) and Transportation (R). The marginal abatement cost for industry E is given by: MACE(XE)= 6X5, where Xp is E’s abatement of GHG's. The marginal abatement cost for industry R is given by MACR(XR)= 4XR, where Xris R's abatement of GHG's. The public decides that in order to stabilize the climate, total abatement of XR + XE = 20 is needed. a. What is the cost-minimizing allocation of abatement effort between the two industries? (Recall Equimarginal Principle II). (4 pts) b. What GHG tax would lead industries E and R to choose the levels of abatement you found in (a)? Demonstrate graphically for industry E. (4 pts)