a nurse is caring for a client with metastatic breast cancer who is extremely lethargic and very slow to respond to stimuli. the laboratory report indicates a serum calcium level of 12.0 mg/dl, a serum potassium level of 3.9 meq/l, a serum chloride level of 101 meq/l, and a serum sodium level of 140 meq/l. based on this information, the nurse determines that the client's symptoms are most likely associated with which electrolyte imbalance?