You have successfully sold and installed your customer’s System x solution. Sometimes， the overall succeed of a sale depends on how well you have trained your customer to support their new hardware. Please consider the following tools. Which one would be the best for protectively determining a server outage， and contacting the system administrator about the outage？（）

A. CDAT
B. Configuration and Options Guide （COG）
C. Physical Alarm Sounding in Data Center
D. IBM Systems Director