This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and Reproduction, Subject name: Physiology
[{'content': 'A 63-year-old man recently treated for renal tuberculosis presents with weight loss, diarrhea, hypoglycemia, hypotension, and is noted to have hyperpigmented buccal mucosa, palmar and hand creases. Which investigation is most suitable for this clinical presentation? \nSelect and explain. \nA. Serum iron and ferritin, B. Serum copper and ceruloplasmin, C. Plasma ACTH and cortisol, D. Gene XPERT and Intravenous pyelography', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. C Plasma ACTH and cortisolRef: CMDT 2019 page 323* The key finding of hyperpigmentation of buccal mucosa, palmar and sole creases point to etiology of Addison disease. The leading cause of Addison's disease in India is tuberculosis.* The presence of hypotension indicates hypoaldosteronism in Addison's disease. Simultaneous mention of hypoglycemia indicates cortisol deficiency.* Choice B is done in case of hemochromatosis and bronze diabetes* Choice C is done in case of Wilson disease* Choice D is done in for diagnosis of tuberculosis", 'role': 'assistant'}]