Who of these is the best description of a monopoly?

A monopoly is a market structure where a single seller or producer dominates the entire market for a particular good or service, effectively eliminating competition. This entity has significant control over pricing and supply, often leading to higher prices and reduced consumer choice. Monopolies can arise due to various factors, including barriers to entry, exclusive resource control, or government regulation. Overall, they can result in inefficiencies and potential exploitation of consumers.