Explanation:

A natural monopoly is a distinct type of monopoly that may arise when there are extremely high fixed costs of distribution, such as exist when large-scale infrastructure is required to ensure supply. Examples of infrastructure include cables and grids for electricity supply, pipelines for gas and water supply, and networks for rail and underground. These costs are also sunk costs, and they deter entry and exit. It may be more efficient to allow only one firm to supply to the market because allowing competition would mean a wasteful duplication of resources.