This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Surgery
[{'content': 'Most common cause of hypersecreting pitutary tumor is? \nSelect and explain. \nA. Pitutary adenoma, B. Pitutary carcinoma, C. Autoimmune disease of pituitary, D. Transection of stalk', 'role': 'user'}, {'content': "Answer: A \nExplanation: ANSWER: (A) Pitutary adenomaREF: Harrison's 18th ed chapter 339, 341Most common cause of hypersecreting pitutary tumors is pitutary adenoma", 'role': 'assistant'}]