You configured an interface with an IP address and committed the change. You then committed a change that added an exception in a firewall filter to allow this network through the filter. You realize that this work was done on the wrong router. How do you undo all these changes?（）

A. Multiple users can enter configuration mode and have their own private configuration.
B. When a user commits, only the user's changes are committed.
C. A message indicates which other users are in configuration mode and what portion of the configuration they are editing.
D. Only a single user can edit the configuration.

A. All users have their own active configuration.
B. All users have their own private candidate configuration.
C. When a user commits, all nonconflicting changes made by all users are committed.
D. When a user commits, only the user's own changes are committed.