Total fixed costs decrease as output expands

When a firm has economic profits equal to zero

A) the firm is earning a normal rate of return on investment. B) the firm is not earning a normal rate of return on investment. C) the firm should shut down. D) the firm's accounting profits are also zero.

Under monopsony, marginal factor cost is

A) equal to the wage rate. B) below the wage rate but increases as more workers are hired. C) greater than the wage rate. D) downward sloping.