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: Surgery
[{'content': "Causes of thyrotoxicosis includes all of the following except: \nSelect and explain. \nA. Grave's disease., B. Struma ovarii., C. Toxic adenoma., D. None.", 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]