You are answering a USMLE-style medical question. Question: A 26-year-old woman comes to the physician because of fatigue, weight loss, and muscle aches during the past 2 months. There is no personal or family history of serious illness. Her only medication is a multivitamin. A metyrapone stimulation test is performed and the results rule out a diagnosis of adrenal insufficiency. Which of the following changes in laboratory findings are most likely to have been observed in this patient following the administration of the drug? Options: A) Increase in serum ACTH B) Decrease in urinary 17-hydroxycorticosteroids C) Decrease in serum 11-deoxycortisol D) Increase in serum cortisol Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.