Which Description of the N8000 Clustered NAS File System Snapshot

Which description of the N8000 Clustered NAS file system snapshot features and their application is wrong?

A) Snapshot file system can be dedicated as a separate space to the client.
B) For a file system can create multiple snapshots, support snapshots of the snapshot
C) Snapshot file system provides only read-only access to external, it cannot provide write operations
D) File System Snapshot Instantly copy the source file system completely available copy, when due to viruses or man-made misuse and other causes of the original file system is not available, the rollback of the snapshot can restore the original file system.