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': 'Volume determining preload is: \nSelect and explain. \nA. End diastolic volume of ventricles, B. Endo systolic volume, C. Volume of blood in aoa, D. Ventricular ejection volume', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e End diastolic volume of ventricles According to frank-starling law, the length of muscle fibers (extent of the pre-load) is propoionate to the end diastolic volumeQ', 'role': 'assistant'}]