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': 'Preload is increased by \nSelect and explain. \nA. Increased blood volume, B. Increased total peripheral resistance, C. Standing, D. Sitting', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The amount of pressure on the muscles before the contraction starts is the preload. In regards to heart, preload is the amount of pressure on the ventricles at the end of diastole. That is the amount of blood which remains in the ventricles at the end of the diastole.', 'role': 'assistant'}]