A fire department is required to have a __________ to track personnel and assignments at an emergency scene.

A Personal Accountability System is critical for tracking personnel and their assignments during an emergency response. This system ensures that all responders can be accounted for at all times, thereby enhancing safety and operational efficiency. In high-pressure situations, such as firefighting, knowing precisely who is on scene and their designated roles helps to maintain coordination and prevent confusion, which is vital for both scene management and the well-being of the firefighters involved.

The Personal Accountability System is specifically designed to log in personnel as they enter a scene, track their assignments, and facilitate their exit when they've completed their tasks. This thorough tracking helps to mitigate the risks of personnel becoming lost or unaccounted for during chaotic incidents.

In contrast, while communication systems are essential for conveying information, they do not inherently track personnel. The Incident Command System provides the overarching structure for managing incidents but relies on the effectiveness of accountability systems to keep track of individual responders. Resource management systems focus more on the allocation and inventory of equipment and supplies rather than personnel accountability, making the Personal Accountability System the most suitable response to the question posed.