What action should the dive supervisor take once a diver is surfaced?

The appropriate action for the dive supervisor to take once a diver has surfaced is to ensure that the diver is treated according to established protocols. This is critical because divers may be exposed to various hazards during their dive, including changes in pressure, potential nitrogen narcosis, or other physiological issues. Following established protocols ensures that the diver receives a thorough evaluation for any signs of decompression sickness or other injuries.

In doing so, the supervisor can conduct a proper medical assessment, monitor the diver's vital signs, and initiate treatment if necessary. This step is essential for the safety of the diver and in accordance with best practices in diving operations. Effective communication and adherence to protocols can significantly reduce the risk of complications after surfacing.

Other options may not adequately address the immediate needs and safety of the diver. Ignoring the diver after surfacing fails to acknowledge the potential risks and necessary assessments. Inflating the diver's buoyancy compensator, while important in certain contexts, may not be the first action in medical evaluation or safety checks. Allowing the diver to fix equipment independently could lead to oversight of potential medical issues that should be addressed by the dive supervisor.