Final answer:
The most appropriate immediate treatment for an athlete with external heatstroke is to move the athlete into an air-conditioned room and provide fluids.
Step-by-step explanation:
The most appropriate immediate treatment for an athlete with external heatstroke is to move the athlete into an air-conditioned room and provide fluids. Option c) is the correct answer.
When an athlete experiences heatstroke, it is crucial to immediately remove them from the hot environment and into a cooler area. Air conditioning helps lower the body's temperature more effectively than using ice bags or full-body ice immersion, which can actually lead to shock. Providing fluids is also essential for hydration and to replace the fluids lost through sweating.
Transporting the athlete to a health-care facility may still be necessary, but the immediate focus should be on cooling them down and providing fluids.