Which of the following best describes a VPN?

A VPN, or Virtual Private Network, serves as a secure and encrypted connection over the internet that allows users to access private networks remotely. It effectively creates a private network by encapsulating and encrypting data being transmitted, which helps maintain confidentiality, integrity, and security while in transit. This technology is crucial for businesses and individuals looking to protect sensitive information while using public or unmanaged networks.

The other options do not accurately encapsulate the core function of a VPN. A public network for file sharing lacks the privacy and security features that define a VPN. Meanwhile, a physical connection between two offices does not represent the virtual aspect of a VPN, as it focuses on tangible connections rather than remote access and encryption. Lastly, a wireless network for mobile devices refers to connectivity primarily related to mobility, without addressing the secure, private nature of a VPN.