Answer :
A competitive firm in the short run can determine the profit-maximizing output by equating Marginal revenue and marginal cost. So, the correct answer is (a).
Short run is a concept in which for a specific period of time at least one input remains fixed while others remain variable. Maximizing profits in the short run. A company chooses to manufacture at the level where its marginal revenue and marginal cost are equal in order to achieve maximum profits. When marginal revenue is higher than marginal cost, the business can increase output and generate more revenue. The firm is in the red and must lower its output when marginal revenue is less than marginal cost. As a result, the firm's profits are maximized when it picks an output level in which its marginal revenue and marginal cost are similar.
Learn more about short run profit maximization here:
https://brainly.com/question/28190349
#SPJ4