What is a possible reason the job failed?

An administrator has a backup for client Linux1using the LinuxClients policy complete successfully.

Even though the policy Backup Selections are NOT modified, the backup job fails the next day with the following status code:

Error 71: none of the files in the file list exist.

What is a possible reason the job failed?
A . The “Enable granular recovery” option was unset.
B . The client was added to another backup policy.
C . The file systems have been unmounted on the client.
D . The client was temporarily shut down.

Answer: C