An older adult nursing home resident who has always been alert and oriented is now showing signs of dehydration and has become confused. Which electrolyte imbalance is most likely involved?

A. Hypomagnesemia can cause neuromuscular and cardiac symptoms but is less commonly associated with acute confusion due to dehydration. B. Hypercalcemia may cause confusion, but it is usually associated with other chronic conditions rather than acute dehydration. C. Hypernatremia is the most likely electrolyte imbalance in this scenario. In older adults, dehydration leads to elevated sodium levels, which can cause confusion, lethargy, and neurological changes. D. Hyponatremia typically results from fluid overload or excessive water intake and is less likely to occur with dehydration in this context.