PLE-6273

A 67-year-old man is hospitalized for treatment of renal insufficiency. Three days after admission, his pulse is 40/min. An ECG shows tall, tented T waves. Serum studies show a sodium level of 134 mEq/L, potassium level of 6.9 mEq/L, and glucose level of 85 mg/dL. What is the most appropriate next step in management? Is it intravenous administration of which of the following?