What is the most likely cause of this behavior?

An administrator is migrating their old cloud tier-enabled Data Domain to a new PowerProtect DD appliance with cloud tier. During migration, the administrator recognizes that file system cleaning on the source system is not possible.

What is the most likely cause of this behavior?
A . Filesystem is disabled on source system
B . Source system is running in restricted mode
C . Migration will restrict all activities on both systems
D . Migration will restrict all activities on source system

Answer: D