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': 'Which of the following is the most common origin of cerebral metastasis? \nSelect and explain. \nA. Lung cancer, B. Breast cancer, C. Melanoma, D. Colon cancer', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Lung:\xa040%\nBreast : 10 - 30%\nMelanoma : 5 - 15%\nUnknown : 15%', 'role': 'assistant'}]