A virtual private network protects confidentiality by creating an encrypted communication tunnel between an internal network and an external user, site, or network. This helps prevent unauthorized parties from reading transmitted information over public or untrusted networks. A cloud network is a service environment and does not automatically protect confidentiality. A mobile network provides connectivity but may require additional security controls. An intranet is an internal private network and does not by itself safeguard transmissions to external networks. Internal auditors reviewing remote connectivity should evaluate VPN encryption, authentication, access restrictions, logging, endpoint security, and session controls. Because a VPN is specifically designed to protect external communication with encryption and secure tunneling, Option D is correct.