(b) The table below shows the information on quantity, price and cost of a monopolist. Assume that the fixed cost is $20. Quantity Price Total Variable Cost 10 $9 $20 20 $8 $60 30 $7 $120 40 $6 $200 50 $5 $300 60 $4 $420 Determine the optimal output of the firm and compute the profit or loss of the firm at the optimal output. At what price will the monopolist exit from the industry? (7 marks)