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、the Disk Magic configuration report
• B、an engineer from thetelcom providing the dark fiber
• C、the bandwidth calculations
• D、aCompeteLine analysis