Which of the following would be the BEST solution for a systems administrator to access the graphical user environment of a Linux machine remotely?

VNC (Virtual Network Computing) is a protocol specifically designed to allow remote access to a graphical desktop environment, providing the full GUI experience over a network connection.

KDE is a desktop environment itself, not a protocol or tool for remote access to a graphical environment.

X11 is the underlying windowing system, and while it supports network transparency, directly using X11 over the network for a full desktop experience is often slower and less secure than VNC or SSH X forwarding, and VNC encapsulates X11 sessions for easier remote management.

RPC (Remote Procedure Call) is a protocol for interprocess communication that allows a program on one computer to execute code on another computer, but it is not used for displaying a remote graphical desktop environment.