A commercial Internet hosting facility advertises that it has “N+2” HVAC systems. This means: a. One more HVAC unit than is needed to provide cooling to the entire facility b. Two more HVAC units than...

A commercial Internet hosting facility advertises that it has “N+2” HVAC systems. This means:

a. One more HVAC unit than is needed to provide cooling to the entire facility

b. Two more HVAC units than are needed to provide cooling to the entire facility

c. Spare parts on-hand for two HVAC units

d. Twice the HVAC capacity than is needed to provide cooling to the entire facility