4. A firm has production function Q(L) = al - bL' + c, where a > 0, b > 0 and c > 0. The firm faces a competitive output market with price per unit equal to 2. The firm is also a monopsonist in the labor market with a supply curve w(L) = mL, where m > 0. a Find the monopsonist's optimal level of employment, wage and cost on labor. b) Graph and calculate the deadweight loss of monopsony