You are not allowed to bring the system down to single user mode, but you must back the active / (root) file system.
What can you use to back up your / (root) file system?

A.
UFS Snapshot

B.
Solaris Volume Manager

C.
The devfsadm command

D.
Solaris Management Console

Explanation:

Use UFS Snapshot to create an image of a live file system. Then backup the image.