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': 'Which one of the following does not cause pulsus paradoxus ? \nSelect and explain. \nA. Severe aortic regurgitation, B. Cardiac tamponade, C. Constrictive pericardities, D. Acute severe bronchial asthma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]