Concept:In perfect competition, a firm is a price taker, so its average revenue remains constant at the market price.
Explanation:Average revenue (AR) is the revenue earned per unit sold, which equals the price of the product.
Under perfect competition, the price is fixed by the market and does not change with the firm's output.
Hence, the AR curve is a horizontal straight line at the market price.
Marginal revenue (MR) is the additional revenue from selling one more unit, which also equals the same constant price.
Therefore, the AR curve and the MR curve coincide as a single horizontal line.
This means the average revenue curve is exactly the same as the marginal revenue curve.
Answer:C. the marginal revenue curve