Which command isolates the system into rescue mode?

• A. Systemctl isolate rescue.target
• B. Systemctl isolate multi-user.target
• C. Systemctl reboot --rescue
• D. Shutdown -r now

Answer: (A)

Systemd uses targets to represent runlevels or modes of operation, and isolating a target switches the system to that mode by starting the target’s units and stopping everything not part of it. Rescue mode is a minimal, single-user environment intended for maintenance. By issuing the command to isolate rescue.target, you explicitly switch the running system into this lean state, bringing up only the essential services and giving you a root shell for repair tasks.

The other commands don’t achieve the same effect. Isolating multi-user.target would drop you into a non-graphical multi-user environment, not rescue. Rebooting with a rescue option or rebooting at all will restart the system into rescue mode on boot, rather than changing the current running state without a reboot.