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': 'Phaeochromocytoma arises from - \nSelect and explain. \nA. Adrenal gland, B. Mediastinum, C. Chest wall, D. Neck', 'role': 'user'}, {'content': 'Answer: A \nExplanation: pheochromocytoma is a neuroendocrine tumor of the medulla of adrenal gland ( Harrison 17pg 2270)', 'role': 'assistant'}]