An insurance customer installs two BladeCenter chassis in a rack with glass doors. After a short time， the blowers in both BladeCenters increase to full speed， and then one fails. Apart from replacing the broken blower， which additional action is required for a long term fix of the following？（）

• A、Add Rear Door HeateXchanger
• B、Add fans to the top of the racks
• C、Increase circulation from Data Center raised floor
• D、Change to perforated doors