This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'Cardiac output is determined by \nSelect and explain. \nA. Ratio of organ to total peripheral resistance, B. Mean stroke volume, C. Mean BP, D. Contractility of hea', 'role': 'user'}, {'content': "Answer: B \nExplanation: Cardiac o/p=stroke volume*Hea rate Therefore cardiac o/p is collectively regulated by Stroke volume and Hea rate Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No: 514", 'role': 'assistant'}]