In the Mirroring Scenario of OceanStor VIS6600T, an Engineer Detected

In the mirroring scenario of OceanStor VIS6600T, an engineer detected an abnormal mirroring alarm on the VIS6600T. When you login to the ISM interface, you can view the mirror status of the volume in the corresponding logical disk group based on the alarm and find that the status of a volume in the mirror is NODEVICE. The reason may be: (multiple choice)

A) The disk on the array on which the failed mirrored volume failed
B) Array where the failed mirrored volume is powered down
C) The RAID array is degraded on the array where the failed mirrored volume is residing, and the hot spare is being rebuilt
D) All optical links between the VIS 6600T and the array in which the failed mirror volume is located have failed