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 index is defined as \nSelect and explain. \nA. Stroke volume M2/BSA, B. Cardiac output per minute per unit body surface area, C. Systolic pressure/M2 BSA, D. End diastolic volume', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Cardiac index- Cardiac output per minute per square meter of body surface area. Normal- 3.2L/min/ m2.', 'role': 'assistant'}]