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: Physiology
[{'content': 'Cardiac output depends on all of the following except: September 2005 \nSelect and explain. \nA. Cardiac rate, B. Body surface area, C. Stroke volume, D. Cardiac contractility', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Body surface area Cardiac Output (CO) = Stroke Volume x Hea Rate Normal SV is 70 mL and hence in a supine, resting man CO is 5.0 L/ min. (70 mLX 72 beats/min.) Cardiac Index (CI) = CO/ Body Surface Area (BSA) = SV x HR/BSA CI averages 3.2L', 'role': 'assistant'}]