Answer: B: MonopolyExplanation:In a Monopoly market, the following features are observed:- Single seller: There is only one firm or seller producing the product or offering the service.- No close substitutes: The product or service offered by the monopolist has no close substitutes, making it unique.- Price maker: The monopolist is the price maker and has control over the price of the product or service.- High barriers to entry: There are high barriers to entry for other firms, either in the form of legal restrictions or economies of scale.MR Curve = AR = Demand Curve:In a monopoly market, the Marginal Revenue (MR) curve, the Average Revenue (AR) curve, and the Demand curve are equal. This is because the monopolist is the sole seller and has control over the price. The demand for the product or service is determined by the price set by the monopolist. Since there is only one seller, the average revenue is equal to the price, and the marginal revenue is the additional revenue earned by selling one extra unit. Therefore, MR = AR = Demand Curve in a monopoly market.

Perfect Competition Market

In a perfect competition market, there are numerous buyers and sellers, and no single buyer or seller has control over the market. The market is characterized by the following features:

Homogeneous Products: The products sold in the market are identical, and there is no differentiation between them.

Perfect Information: All market participants have access to complete information about the market, including prices, quality, and availability of goods.

Free Entry and Exit: There are no barriers to entry or exit in the market, allowing new firms to enter or existing firms to exit the market freely.

Price Takers: Each firm in the market is a price taker, meaning they have no control over the price of the product and must accept the market price.

MR Curve = AR = Demand Curve

In a perfect competition market, the demand curve faced by a firm is perfectly elastic, meaning that the firm can sell any quantity of output at the market price. As a result, the marginal revenue (MR) curve faced by the firm is also equal to the average revenue (AR) and demand curve.

This is because in a perfect competition market, the price is determined by the interaction of market demand and supply, and individual firms have no influence on the market price. Therefore, the firm faces a horizontal demand curve, and any increase in output sold will result in a decrease in the unit price of the product, leading to a constant MR curve.

Conclusion

In conclusion, the MR curve = AR = demand curve is a feature of a perfect competition market, where individual firms have no control over the market price and face a horizontal demand curve. This condition ensures that the market is efficient and allocates resources optimally, leading to the welfare of the society as a whole.