This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'A 25 year old male presnents with weakness, occasional vomiting hypotension, skin and mucous membrane pigmentgation. The diagnosis can be best established by - \nSelect and explain. \nA. Metyrapone test, B. Basal plasma Coisol levle, C. 24-hour urinary 17-Ketosteroid, D. ACTH stimulation test', 'role': 'user'}, {'content': 'Answer: D \nExplanation: after administration of ACTH , coisol level increases. This can be used as an index of the functional reserve of adrenal gland for production of coisol ( Harrison 17 pg 2252)', 'role': 'assistant'}]