What is a private network accessible only to authorized users called?

A private network that is accessible only to authorized users is referred to as an intranet. An intranet is designed to be a secure environment where members of an organization can share information, conduct communications, and manage data within a limited user base. This access restriction ensures that sensitive information remains within the organization and is not exposed to the general public.

Intranets are commonly used by businesses and institutions to enhance internal communication and collaboration, providing tools like file sharing, internal websites, and messaging systems that are specifically tailored for the users within the organization. Because it is confined to an organization's network, only authenticated users can access the resources and information available on the intranet.

The other options represent different networking concepts. The internet is a global network that is accessible to anyone with a connection. Extranets extend access to certain external users such as partners or customers but are not as restricted as an intranet. A VPN, or Virtual Private Network, allows users to connect securely over the internet to a private network, but the concept of a private network itself specifically refers to an intranet rather than the technologies used to access it.