This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Pheochromocytoma is a tumour of the: \nSelect and explain. \nA. Adrenal cortex, B. Parathyroids, C. Pituitary, D. None of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Most adrenal\xa0medullary\xa0tumors\xa0(pheochromocytomas)\xa0secrete norepinephrine or epinephrine or both and produce sustained hypertension.\nPheochromocytoma is a tumour of the adrenal\xa0medulla.\nReference: Ganong’s Review of Medical Physiology T W E N T Y - F I F T H\xa0 \xa0E D I T I O N page no 356', 'role': 'assistant'}]