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': 'A metastatic carcinoma in the brain of an adult, most often comes from primary in the \nSelect and explain. \nA. Stomach, B. Ovary, C. Oral cavity, D. Lung', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e. Lung", 'role': 'assistant'}]