Just CDs, Inc., has developed a booming business in the purchase and sale of used CDs and used DVDs. Demand and marginal revenue relations for the local college student market are: P-$6-$0.00005Q MR$6- $0.0001Q TC-$4Q Mr=MC Fixed costs are zero, and marginal costs are constant at $4 per unit. a. if Just CDs enjoys an effective monopoly in the local market, Calculate the profit- maximizing a. Output (5pts)