What should lifeguards do if they notice an injury on a swimmer?

The correct choice emphasizes the critical actions lifeguards must take when witnessing an injury on a swimmer. Assessing the injury is the first step, as it allows the lifeguard to determine the severity of the situation and the appropriate response. Providing first aid is essential for ensuring immediate care, which can alleviate pain, prevent further injury, or address any medical needs that arise from the injury. Finally, documenting the incident is vital for record-keeping and provides important information for any subsequent medical professionals who may treat the swimmer or for any legal documentation related to the incident. This systematic approach ensures the safety and well-being of the swimmer while fulfilling the lifeguard's responsibilities.

The other options lack a comprehensive response to an injury. Ignoring the injury can exacerbate the situation if the swimmer requires assistance but does not voice their discomfort. Calling for an ambulance without assessing the injury may lead to unnecessary emergency responses, which can burden emergency services and divert attention from those who might need urgent care. Suggesting the swimmer take a break without addressing the injury could leave the swimmer in a vulnerable position and does not fulfill the obligation lifeguards have to ensure the well-being of all patrons in the pool.