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': 'Pulsus paradoxus is a characteristic feature of \nSelect and explain. \nA. Constrictive pericarditis, B. Cardiac Tamponade, C. Hypertrophic obstructive cardiomyopathy, D. Restrictive cardiomyopathy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]