In perfect competition, the average revenue curve of a firm is

In perfect competition, the average revenue curve of a firm is identical to the marginal revenue curve. This is because in a perfectly competitive market, a firm is a price taker, which means that it cannot influence the market price and must sell its output at the prevailing market price. Since the market price is constant, the average revenue curve is also constant at that price. Meanwhile, the marginal revenue curve represents the additional revenue earned by the firm for each additional unit of output sold. In perfect competition, this additional revenue is equal to the market price, which is constant. Therefore, the marginal revenue curve is also constant and identical to the average revenue curve. Hence, the correct answer is: the marginal revenue curve.