A technician needs to perform remote maintenance on devices across the network.

The correct answer is D. SSH . Secure Shell is the best choice because it provides encrypted remote administrative access and is commonly supported across platforms, especially Linux, UNIX, macOS, network devices, and modern Windows systems. Quentin Docter’s Complete Study Guide explains that SSH is commonly used for remote access through a text console, encrypts communication between the SSH client and server, and uses TCP port 22. It also supports authentication through public/private key pairs or username and password credentials. The Mike Meyers/Mark Soper material also identifies SSH as the secure modern replacement for Telnet and explains that the entire connection is encrypted to pre vent eavesdropping. VNC is cross-platform, but it is not encrypted by default and often requires plug-ins for encryption. RDP is mainly associated with Windows graphical remote access, and VPN provides secure network connectivity but is not itself a remote maintenance shell or control tool.