Which class involves a single building with only one telecom area?

The correct answer is Class 1, as this classification specifically pertains to a single building that contains only one telecommunications area or space. In telecommunications standards, a Class 1 environment represents a simpler network structure where all telecommunications functions and equipment are centralized in a single location. This setup typically allows for easier management and maintenance of the telecom systems, as technicians can address all telecommunications needs from one area without the complications of multiple sites or telecommunication points.

Classes 2, 3, and 4 involve more complex structures with multiple telecommunications areas or buildings, which increases the variety of potential configurations and necessitates a broader range of management strategies and considerations. By concentrating all telecom operations within a single space in Class 1, it streamlines operations and can lead to efficiencies in both design and maintenance.