A competitive firm has been selling its output for $20 per unit and has been maximizing its profit, which is positive. Then, the price rises to S25, and the firm makes whatever adjustments are necessary to maximize its profit at the now-higher price. Once the firm has adjusted, its :.
a. quantity of output is higher than it was previously.
b. average total cost is higher than it was previously.
c. marginal revenue is higher than it was previously.
d. all of the above are correct.

White truffles are a very prized and rare edible fungus that grow naturally in the countryside near alba, italy. suppose that it costs $200 per day to search for white truffles. on an average day, the total number of white truffles (t) found in alba is t = 20x − x 2 , where x is the number of people searching for white truffles on that day. white truffles can be sold for $100 each. if there is no regulation, how many more people will be searching for white truffles than the socially optimal number?