A customer has installed an IBM System Storage DS8700 with 20 TB of storage， two-way processor version， 32 GB cache， and 16 Fibre Channel ports. The customer is beginning to experience throughput performance issues.  To address this performance consideration with minimal cost to the customer， which of the following should be the FIRST step to resolve the problem（）

• A、add an expansion frame with additionalFibre Channel ports
• B、increase the amount of storage by 20 TB
• C、conduct a Disk Magic study to identify the source of the performance issue
• D、add additionalFibre Channel ports to the existing DS8700