The correct answer is C. A price taker is a firm that cannot affect the market price of its product. This means that the firm must accept the market price as given and cannot charge a higher price. As a result, the demand curve for a price taker is perfectly elastic. This means that the firm can sell any quantity of output at the market price, but if it tries to charge a higher price, it will sell no output.
Option A is correct because the total revenue of a price taker is equal to the price of its product times the quantity of output it sells.
Option B is correct because the average revenue of a price taker is equal to the price of its product.
Option D is correct because the marginal revenue of a price taker is also equal to the price of its product. This is because a price taker can sell any additional quantity of output at the market price, so its marginal revenue is equal to the price.
Option C is incorrect because a price taker does not have a negatively sloped demand curve. As explained above, the demand curve for a price taker is perfectly elastic.