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': 'Most common cancer that metastasizes to leptomeninges : \nSelect and explain. \nA. Lung cancer, B. Breast cancer, C. Prostate cancer, D. Ovarian cancer', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most common cancer that metastasizes to brain : Lung cancer.\nMost common cancer that metastasizes to leptomeninges : Breast cancer.', 'role': 'assistant'}]