To begin, a competitive firm is selling its output for $20 per unit and it is maximizing its profit, which is positive. Now, the price rises to $25 and the firm makes whatever adjustments are necessary to maximize its profit at the now-higher price. Once the firm has adjusted, which of the following statements is correct?
a. The firm's quantity of output is higher than it was previously,
b. The firm's average total cost is higher than it was previously,
c. The firm's average revenue is higher than it was previously,
d. All of the above are correct.