Consider a competitive market with a large number of identical firms. The firms in this market do not use any resources that are available only in limited quantities. In long-run equilibrium, market price is determined by

a. the minimum point on the firms' average variable cost curve.
b. the minimum point on the firms' average total cost curve.
c. the portion of the marginal cost curve below average variable cost.
d. a firm's level of sunk costs.

b