Customers to migrate to the 6-core Power6 520 S814, Which backplane RAID 5 provides the best performance ?

A.
detachable back with 6 + 6 SFF-3 bracket and the second SAS controller

B.
with ( 12 ) SFF-3 bracket and integrated SAS storage controller backplane

C.
with ( 18 ) SFF-3 bracket and dual SAS controllers and write cache storage backplane

D.
detachable back with PCIe3 12GB Cache RAID SAS adapter and EXP24S of