A client is admitted with diabetic ketoacidosis (DKA) and is receiving an IV infusion of 0.9% sodium chloride and insulin. Two hours later, the client's serum laboratory results show a decrease in the serum blood glucose from 580 to 430 mg/dL (32.2 to 23.86 mmol/L). It is most important for the nurse to monitor which additional laboratory result? Reference Range

A. Serum potassium. Insulin therapy causes potassium to move into cells, which can lead to hypokalemia. Monitoring serum potassium is critical because significant drops can lead to cardiac arrhythmias and other complications. B. Urine ketones. While monitoring ketones is important for assessing the resolution of DKA, it is not as immediately critical as monitoring potassium levels. C. Serum sodium. Sodium levels are important but typically do not change as rapidly as potassium levels during DKA treatment. D. Blood urea nitrogen (BUN). BUN levels provide information about kidney function and hydration status but are less immediately critical than potassium levels in the context of insulin therapy for DKA.