What is a precaution when working with Dell PowerScale equipment?

What is a precaution when working with Dell PowerScale equipment?
A . Nodes can operate below 5 degrees C, but only for limited periods of time
B . The total rack load should not exceed 70% of the branch circuit rating
C . Use side stabilizers if the rack is not bolted to the floor
D . Connections to the branch circuit need not be properly grounded

Answer: A