Where is the Mdisk data encryption key stored?

A customer has a data at rest encryption requirement. You have suggested the IBM Storwize V7000 model 524 system to replace the older IBM Storwize V7000 model 124 storage systems.

Where is the Mdisk data encryption key stored?
A . On the SAS interface chip on the drive
B . In secure memory in SAS controller hardware
C . On an external device when encryption is enabled
D . In the secure management area on the quorum disk

Answer: B