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: Unknown
[{'content': 'Pulse pressure in a particular vessel is determined chiefly by: \nSelect and explain. \nA. Distance from heart, B. Frictional characteristics of lumen, C. Distensibility, D. Cross-sectional area', 'role': 'user'}, {'content': 'Answer: C \nExplanation: In advancing age due to loss in elasticity of blood vessels, stretching decreases which results in increased pressure during systole with normal diastolic blood pressure (systolic hypertension). The blood vessels behave like a rigid tube. It is characterized by high pulse pressure. Pulse pressure is determined by elasticity of vessel wall that varies inversely with total peripheral resistance.', 'role': 'assistant'}]