First aid should only be administered in an emergency when which condition is met?

First aid should be administered in an emergency primarily when the individual providing the assistance is not in danger. This is crucial because if the rescuer puts themselves in harm's way, they could become another victim and potentially worsen the situation. It is essential to ensure a safe environment for both the first aid provider and the person in need of assistance.

If the situation poses a risk to the responder, they may not be able to effectively help the injured person, and their safety must come first. In many emergencies, the well-being of the responder allows them to assess the situation accurately, provide the necessary care, and may also enable them to call for further help if needed.

The other choices do not present the same level of priority. For instance, a situation being life-threatening may indeed require immediate action from someone in a safe position, while the availability of medical personnel, while important, should not deter a trained individual from providing needed care. Similarly, common sense is a vital component in emergencies, but if it leads the rescuer to enter a dangerous situation, it risks not only their safety but the safety of those involved.