Refer to the Exhibit.

A company has three data centers and has decided to protect its data using SRDF. The replication design must ensure there will be no data loss if Site A fails. All data centers are within 200 km of each other. Either Site B or Site C should be able to take over as production sites in the event of the failure of Site A.
How should SRDF be configured between Sites A and B, and how should devices be configured at Site B?

A.
SRDF/S between Sites A and B with disk-based R21 devices at Site B

B.
SRDF/A between Sites A and B with disk-based R21 devices at Site B

C.
SRDF/S between Sites A and B with disk-less R21 devices at Site B

D.
SRDF/A between Sites A and B with disk-less R21 devices at Site B