Which of the following is considered an appurtenance?

An appurtenance refers to a right, privilege, or improvement that is associated with a piece of real property. In this context, an easement is classified as an appurtenance because it grants a specific right to use another person's property for a designated purpose, such as access or utility installations. This right is not just a standalone interest but is tied to the land itself; when the property is sold, the easement typically remains in effect and transfers with the property ownership, thus enhancing the value or usability of the land.

In contrast, the other choices—such as a swimming pool, garden shed, or real estate sign—are more transient or discretionary in nature. While they can be important features of a property, they do not carry the same enduring legal rights or privileges as an easement. For example, a swimming pool or garden shed may be considered fixtures or improvements on the property, but their ownership does not involve the perpetual rights associated with an easement. A real estate sign serves primarily a temporary marketing function and also lacks the enduring nature and legal significance of an easement.