A firm hires labor in a perfectly competitive labor market. Its current profit-maximizing hourly output is 100 units, which the firm sells at a price of $5 per unit. The Marginal Physical product (MPP) of the last unit of labor employed is 5 units per hour. The firm pays each worker an hourly wage of $15. a) What Marginal Revenue (MR) does the firm earn from sale of the output produced by the last worker employed? b)Does this firm sell its output in a perfectly competitive market