In contrast to a perfectly competitive firm, a monopolist operates in the long run at a quantity of output at which a. \(P=M C\) b. \(M R=M C\) c. \(P=A T C\) d. \(P > M R\)

A monopolist is a single seller in the market, which means that it can exercise control over the price and quantity of the product. In contrast, a perfectly competitive firm is one of many firms selling an identical product in the market and has no control over the price. Customers can easily switch between these firms so they all act as price takers.

In a perfectly competitive market, a firm earns zero economic profit in the long run. To achieve this, the firm will produce a quantity where Price (P) equals Marginal Cost (MC), meaning \(P = MC\).

a. \(P = MC\), this is the condition for a perfectly competitive firm, not a monopolist. b. \(MR = MC\), this condition states that the monopolist will produce a quantity where its Marginal Revenue (MR) equals its Marginal Cost (MC). This is the profit-maximizing condition for a monopolist. c. \(P = ATC\), this condition states that Price (P) equals Average Total Cost (ATC). While the monopolist may be operating at this point in some cases, it does not encompass the uniqueness of monopolists and can also apply to perfectly competitive firms under some conditions. d. \(P > MR\), this condition implies that the Price (P) of the product is greater than the Marginal Revenue (MR) received by the monopolist for each additional unit sold. This is true for a monopolist, but it does not directly state its profit-maximizing condition. Based on the analysis of each of the given options,

The monopolist operates in the long run at a quantity of output at which: b. \(MR = MC\)