Which of the following leads to the high costs of operating an IT data center?

A$.$ Sufficient air conditioning to eliminate the heat generated by servers and disk$-$storage devices

B$.$ Conditioned power with the potential for uninterrupted power supply in the short term and long term through the use of on$-$site diesel$-$powered generators

C$.$ Fire suppression systems

D$.$ Administrative staffing to support hardware, networks, and operating systems

E$.$ All of these are correct.