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': "All of the following may be seen in patient of cardiac tamponade except- \nSelect and explain. \nA. Kussmaul's sign, B. Pulsus paradoxus, C. Electrical alternans, D. Right ventricular diastolic collapse on echocardiogram", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]