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: Medicine
[{'content': 'Cerebral angiography was performed by \nSelect and explain. \nA. Sir Walter Dandy, B. George Moore, C. Seldinger, D. Egas Moniz', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Egas Moniz", 'role': 'assistant'}]