The correct answer to this open question is the following.
Although there are no options attached, we can say the following.
The roles that David play are basically the ones included in the phase of "response" in emergency management. The four phases of emergency management are Mitigation, Preparedness, Response, and Recovery.
David plays his role in the response phase that includes taking down the necessary information about the caller and the emergency at hand. He also instructs an emergency unit to reach the emergency site and handle the situation. His first priority is helping people in need, saving lives, and avoid further damage on the site. David has to act swiftly in a calm way, rigorously following the response protocol to provide the proper aid in an organized way.
