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: Pediatrics
[{'content': 'Pheochromocytoma is the disease of: \nSelect and explain. \nA. Pituitary gland, B. Adrenal medulla, C. Pancreas, D. Adrenal cortex', 'role': 'user'}, {'content': "Answer: B \nExplanation: b. Adrenal medulla(Ref: Nelson's 20/e p 2227-2729, Ghai 8/e p 525)Pheochromocytoma is a neoplasms of chromaffin cells in medulla that release catecholamines.", 'role': 'assistant'}]