This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
[{'content': 'A 68-year old man who has had a recent syncopal Episode is hospitalized with congestive hea failure failure. His blood pressure is 160/80 mm Hg. His pulse rate is 80 Beats minute,and there is agrade lll/lV harsh systolic murmur. \nSelect and explain. \nA. Radiation of the murmur to die neck., B. Decrease of me murmur with handgrip, C. Delayed carotid upstroke, D. Reduced left ventricular ejection fraction', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Carotid upstroke. A delayed upstroke (pulsus parvus et tardus) can suggest aoic stenosis, left ventricular outflow obstruction, or significant decrease in stroke volume. Vascular stiffness due to aging can reduce the delay, causing a more normal-feeling upstroke Ref Davidson 23rd edition pg 456', 'role': 'assistant'}]