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: Radiology
[{'content': 'Kerley B lines seen in: \nSelect and explain. \nA. Pleural effusion, B. Mitral stenosis, C. Pericardial effusion, D. All', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Mitral stenosis', 'role': 'assistant'}]