Which command displays available systemd unit types?

• A. systemctl -t help
• B. systemctl list-unit-types --all
• C. systemctl list-unit-types
• D. systemctl help

Answer: (C)

You discover what kinds of units systemd can manage by listing unit types. Systemd organizes resources into unit types such as service, socket, timer, mount, target, path, device, slice, scope, and automount. To see which unit type names are recognized on your system, the direct command is systemctl list-unit-types. It specifically outputs the available unit type names, giving you a clear view of the categories you can work with or filter on when using other systemctl commands. This is the best choice because it is purpose-built to reveal the unit-type list. Other options either show general help or operate on actual units rather than revealing the unit-type catalog.