Which scenario requires immediate first aid attention?

The scenario that requires immediate first aid attention involves a person who is holding their throat and gagging. This situation indicates a potential airway obstruction, which can quickly become life-threatening. If a person's airway is blocked, they may be unable to breathe, leading to serious consequences within minutes. It is crucial to assess the situation promptly and provide assistance, such as performing the Heimlich maneuver, to help dislodge the obstruction and restore airflow.

In contrast, the other scenarios, while they may require some level of medical attention, are not immediately life-threatening. A sprained ankle typically requires rest and ice, but does not pose an immediate risk to life. A person feeling light-headed may need to sit down and rest, or could benefit from hydration, but again, it does not necessitate instant intervention. A mild headache, while uncomfortable, is often not an emergency and can usually be managed with over-the-counter pain relief and rest.