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': 'Myocardial oxygen demand depend upon all except: \nSelect and explain. \nA. Preload, B. Afterload, C. Intramyocardial tension, D. Blood Hb concentration', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Hb concentration determines the O2 supply to myocardium, not myocardial O2\xa0demand.', 'role': 'assistant'}]