​Which of the following is a private network that is typically open to external parties, such as business partners, suppliers, and key customers?​

Correct option is B

• An extranet is a private network that is typically open to external parties, such as business partners, suppliers, and key customers. 
• An extranet is similar to an intranet, but it's designed to provide controlled access to an organization's internal resources to authorized external users.
•  The main purpose of an extranet is to allow users to exchange data and applications, and share information. 
• For example, a widget manufacturer and a company that sells their widgets to the public might set up an extranet to streamline communication and collaboration. 
• The extranet would allow the manufacturer to securely share sales information, pricing, and inventory listings with the company that sells their widgets.