Final answer:
EMS should be activated for an 8-year-old showing confusion and profuse sweating if the child is disoriented and unable to communicate clearly, indicating a potential serious medical issue requiring immediate attention.
Step-by-step explanation:
The school nurse might activate Emergency Medical Services (EMS) for an 8-year-old patient presenting profuse sweating and confusion under the circumstance where the child is responsive but unable to communicate effectively and appears disoriented. This situation corresponds to option C. When a child exhibits such symptoms, it can be a sign of a serious medical condition that warrants immediate assessment and intervention by EMS. Clear communication, orientation, and coherence are critical for assessing a child's condition, and disorientation is a red flag that needs urgent attention.