When a data center is configured such that the backs of the devices face each other and the ambient temperature in the work area is cool, it is called ___________.

Hot aisle containment involves directing the hot exhaust air from the back of server racks into a contained aisle. This configuration ensures that the heat generated by equipment does not mix with the cooler ambient air in the main data center space, allowing for efficient cooling and maintaining a cool work environment.

Cold aisle containment involves enclosing the cool air supply aisle where the fronts of devices receive cold air, which contradicts the description of device backs facing each other.

Thermo-optimized is a general term indicating temperature optimization but does not describe a specific data center physical configuration.

HVAC modulated refers to controlling the heating, ventilation, and air conditioning system's output, not a specific physical layout of equipment in a data center.