Which of the following characteristics defines a monopoly?

In a monopoly market structure, one firm dominates the entire market, allowing it to influence the prices of its products or services. This is known as being a price maker, as the monopolist has the power to set prices above the marginal cost, maximizing its profits and resulting in a lack of competition. The absence of competitors means that consumers have limited alternatives to choose from, which further enables the monopolist to dictate the price.

In contrast, high competition occurs in a market structure with many firms, where individual companies do not have significant control over the price, making the concept of price making irrelevant. Price taking pertains to perfectly competitive markets, where firms accept the market price as given and cannot influence it. Additionally, perfect information is characteristic of idealized markets, particularly perfect competition, where all buyers and sellers have complete knowledge about prices and products, which does not apply to monopolistic situations. Thus, the defining feature of a monopoly is its ability to set prices as it chooses, affirming that being a price maker is the correct distinguishing characteristic.