An EMT has been assigned as the treatment supervisor at a mass casualty incident.

Within the Incident Command System (ICS), the Treatment Supervisor is responsible for overseeing patient care after initial triage has been completed. NREMT instruction clearly differentiates roles to prevent confusion and maintain efficiency.

Option D is correct because the treatment supervisor ensures that secondary triage is completed in the treatment area, allowing patients to be reassessed and reprioritized as their conditions change.

Option A is incorrect because triage personnel are managed by the Triage Supervisor.

Option B is the responsibility of Staging under Logistics.

Option C falls under the Transport Supervisor.

NREMT emphasizes strict role adherence during MCIs to ensure patient flow and resource coordination.