Which of the following is correct about the InfoStamper feature of an OceanStor 9000 storage...

Snapshot does not support nested, that is, the snapshot has been created directory, the parent directory and subdirectories can no longer create a snapshot

The root directory of the snapshot (that is, the directory used to create the snapshot) does not support deletion

Hard links are protected by snapshots, soft links are not protected by snapshots

For a snapshot with an expiration time set, the system automatically deletes the snapshot but does not back up the storage space occupied by the snapshot data after the snapshot expires