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
Which one of the following does not cause pulsus paradoxus ? 
Select and explain. 
A. Severe aortic regurgitation, B. Cardiac tamponade, C. Constrictive pericardities, D. Acute severe bronchial asthma
A: Severe aortic regurgitation
Answer: A: Severe aortic regurgitation 
Explanation: None