What is the procedure for handling a diver who is unconscious underwater?

The correct answer is grounded in established emergency response protocols for divers. When a diver becomes unconscious underwater, immediate action is necessary to ensure their safety and increase the chances of survival. The procedure involves performing an emergency ascent to bring the diver to the surface safely. This ascent must be controlled to prevent barotrauma or decompression sickness, which could occur if the diver ascends too rapidly.

Once at the surface, providing surface support means that a rescue team should be ready to assist the unconscious diver. This may involve stabilizing the diver, preventing drowning, and preparing for further intervention. Initiating CPR is critical if the diver is not breathing or does not have a pulse. CPR can help maintain blood circulation and oxygenation until advanced medical care is available.

Other options do not align with best practices in emergency responses for unconscious divers. Initiating a breathing exercise underwater is impractical and does not address the diver's immediate need for surface intervention. Leaving the diver to signal for help neglects their condition and could result in drowning or more severe injury. Underwater resuscitation techniques are not typically feasible and could complicate the situation further without bringing the diver to safety first. Thus, the chosen response emphasizes rapid but safe recovery and medical intervention.