Which action should be taken for a person experiencing heat stroke?

Placing ice packs under the knees and wrists is an effective action for someone experiencing heat stroke because it targets areas where blood vessels are close to the surface, allowing for rapid cooling of the body. Heat stroke is a severe condition that occurs when the body's temperature regulation fails and core body temperature rises to dangerous levels. This can happen due to prolonged exposure to high temperatures or strenuous physical activity in hot weather.

By applying ice packs in these areas, you can help lower the person's body temperature more quickly. The cooling effect can prevent further complications that may arise from heat stroke, such as organ damage or heat-related illnesses. This method is a first aid treatment that can stabilize the individual before professional medical help arrives.

Other methods, such as encouraging the person to walk around, would not be appropriate since movement can increase body temperature and lead to further overheating. Having them drink ice-cold water may also not be suitable for severe cases, as the individual could be disoriented or unable to drink safely. Lastly, putting them in a hot environment is contraindicated; it would exacerbate their condition and worsen the heat stroke. Thus, using ice packs in specific areas is a safe and effective measure in the response to heat stroke.