For what reason is having BCVs attached to the R2 devices at the remote site in a SRDF/A configuration recommended?

A.
To preserve a consistent copy of data at the remote site before a split operation.

B.
To mirror R2 devices for backup purpose in a disaster recovery scenario.

C.
To preserve extra tracks that would not fit into the cache of R2’s COVD devices.

D.
To preserve a consistent copy of data at the remote site before a resynchronization operation.