Which of the following is not a source of rents?

The amount of output that a firm decides to sell has no effect on the market price in a competitive industry because

A) the market price is determined (through regulation) by the government B) the firm supplies a different good than its rivals C) the firm's output is a small fraction of the entire industry's output D) the short run market price is determined solely by the firm's technology E) the demand curve for the industry's output is downward sloping

In the long run, firms in a perfectly competitive market produce:

A. at a quantity with positive economic profits. B. where average variable costs are minimized. C. where MC is at its lowest point. D. where price equals marginal cost.