You are answering a USMLE-style medical question. Question: Two hours after undergoing open cholecystectomy for complicated cholecystitis, a 48-year-old woman develops dizziness, lethargy, abdominal pain, and nausea. She has systemic lupus erythematosus and hypertension. Prior to hospitalization, her medications included nifedipine and prednisolone. Her pulse is 112/min and blood pressure is 90/64 mm Hg. Examination shows central obesity. The abdomen is soft and non-tender, and the laparoscopic incisions have no discharge. Her serum cortisol and serum ACTH are decreased. Which of the following additional findings is most likely in this patient? Options: A) Normal anion gap metabolic acidosis B) Hyperkalemia C) Hyperglycemia D) Hyponatremia Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.