8. A retailer is considering two promotion strategies for selling a new product: 25%-off discount or \"4-for-3\" (buy three and get a fourth free, i.e., pay the amount of money for three units and get another unit free.) Use demand curve Q=162P, and original price P*=4. a. Which method is more effective in promoting sales? Show by computing the equilibrium quantity sold under each pricing scheme. b. If the retailer offers both promotions, Which one is more desirable for consumers