A nurse is caring for a client who has hypernatremia and is receiving intravenous (IV) hypotonic fluid replacement. Which of the following manifestations should the nurse understand is an indication of an adverse effect from the administration of hypotonic fluids?

C The client has a positive Chvostek's sign. D The client's blood urea nitrogen (BUN) level is 18 mg/dL (10 to 20 mg/dL). B The client's serum sodium is 140 mEq/L (135 to 145 mEq/L). A The client has developed confusion.