What is the first action to take if a person goes overboard during a refueling evolution?

When a person goes overboard, the immediate priority is to provide flotation assistance to help ensure their safety. Tossing a life ring to them is a rapid and effective way to give them something to hold onto while others respond to the emergency. This action quickly addresses the immediate risk of drowning, allowing the individual to stay afloat until further assistance can be provided.

The other options involve necessary actions that should follow the initial response. Calling for medical assistance is crucial if the individual has sustained injuries, but it shouldn't delay providing flotation support. Signaling for help with a flag or notifying the Duty Officer are also important steps, but they come after ensuring the person in the water has immediate support to keep them safe. Immediately tossing a life ring focuses on preserving life while coordinating the rest of the emergency response.