The correct answer is: D. Intranet
An intranet is a private network that uses Internet technologies to share information, applications, and computing services within an organization. It is a secure network that is only accessible to authorized users, such as employees, customers, and suppliers.
An extranet is a network that is extended to users outside of an organization, such as customers, suppliers, or partners. It is a secure network that is used to share information and applications with authorized users.
Telnet is a text-based protocol that allows users to connect to remote computers and run commands. It is a non-secure protocol that
is not commonly used today.The Internet is a global network of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to serve billions of users worldwide. It is a public network that is accessible to anyone with an Internet connection.