Two DS8700 systems have been proposed for a disk-to-disk BC solution. Each system has 200 TB installed， with a data change rate of 18% per day. Two 2 Gbps CWDM links are in place between the remote data centers with an average utilization rate of 55%. The proposed solution  
includes additional CWDM ports. 
Which of the following should justify the additional CWDM ports（）

A.All types of the 2.5" disk drives offered by the DS8800 system have higher performance than the 3.5" disk drives supported by DS8700
B.The 2.5" disk drives included on the DS8800 support 6Gbps SAS； the 3.5" disk drives in DS8700 are 4 Gbps FC
C.The 2.5" disk drives included on the DS8800 support 8Gbps SAS； the 3.5" disk drives in DS8700 are 4 Gbps FC
D.The 2.5" 15k rpm drives offered by the DS8800 system support 6Gbps SAS-2

A.PowerPath
B.MPIO
C.RDAC
D.SDD

A.it is cost efficient， as a single N series or DS8000 can have its controllers split between the  primary and secondary site and use semi- synchronousmirroring while using asynchronous mirroring to a third site
B.the second site acts as a repeater station so that greater geographical distances can be achieved
C.ITprovides high availability together with disaster recovery by implementing Metro/Global Mirror across three geographically dispersed systems
D.it guarantees data protection by implementing two synchronous copies of the primary site data