The table below records what in the labor market is demanded and supplied in the labor for high school teachers, where the teachers belong to a union. If there were no teachers union in this market environment, what would the equilibrium salary be? Annual Salary Quantity of workers demanded Quantity of workers supplied $20,000 200 50 $30,000 180 70 $40,000 130 90 $50,000 110 110 $60,000 75 120 $70,000 50 150 a. $50,000 b. $40,000 O c. $30,000 d. $60,000