A customer has a new p5-550 running AIX 5.2 that is SAN-attached to a FAStT900.  They have encountered hangs lasting over a minute on their new system during application load testing.  They called the pSeries technical specialist for advice.  Which of the following would be the most appropriate questions to determine their next step in resolving the problem？（）

• A、Are there any errors in the error log？ Do they indicate any hardware or software errors？
• B、Has performance data been collected？ What do the results show in terms of I/O statistics？
• C、Has performance data been collected？ What do the results show in terms of CPU utilization？ 
• D、What type of SAN switch is the customer using？ What are the microcode levels on the switch？