A company has had problems with their HVAC system being able to cool their datacenter as theyhave grown. Which of the following could BEST be used to help reduce the load on the HVACsystem?（）

A. Replacing the CAT5 cables with CAT6 cables
B. Replacing traditional racks with water cooled racks
C. Turning off non-critical application servers during non-business hours
D. Taking the second power supply out of non-critical servers