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': 'Atrial fibrillation is seen in all except: \nSelect and explain. \nA. Constrictive pericarditis, B. Atrial septal defect, C. Mitral stenosis, D. Ventricular septal defect', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]