10. The diagram shows the price, marginal cost, and average cost curves facing a perfectly competitive firm in the short run. What is the firm's profit-maximizing output in the short run?
60 units
80 units
100 units
140 units
11. In the long run, will the industry adjust so that the market supply curve shifts sufficiently to allow all firms to make a normal profit?
a) Existing firms exit; right; drop
b) New firms enter, right; drop
c) Existing firms exit; left, rise
d) New firms enter; left, rise