A previously functional， scheduled snapshot operation against a JFS2 filesystem has failed. The JFS2 filesystem is mounted and appears intact.  What is the most likely cause of the failure and how should it be resolved？（）  

• A、The associated JFS2 log device has failed. Check the log device and varyon the device.
• B、The logical volume that hosts the snapshots is full. Increase the size of the logical volume.
• C、Fifteen snapshots already exist for the given JFS2 filesystem. Delete at least one existingsnapshot.
• D、The volume group that hosts both the snapshots and JFS2 filesystem has lost quorum. Check and correct the integrity of the volume group.