A customer has installed an IBM System Storage DS8700 with 20 TB of storage, 32 GB cache, and 16 Fibre Channel ports. The customer is beginning to experience throughput performance issues since they have added new workloads. The customer asks the storage specialist for guidance. Which of the following actions should be recommended as a first step?（）

• A、install the Performance Accelerator feature
• B、review the DS Storage Manager Major Event Log (MEL)
• C、add an expansion frame with additionalFibre Channel ports
• D、review the latest TPC for Disk study to identify the source of the performance issue