Sensors, specifically temperature sensors in this context, play a key role in monitoring the environmental conditions within a NOC. Ensuring that the temperature stays within safe limits is critical to prevent hardware from overheating, which can lead to equipment damage, system failures, and downtime. High temperatures can reduce the lifespan of devices and impact performance. The incorrect answers deal with other aspects of environmental monitoring or network management, which though important, don't directly relate to the prevention of overheating hardware.