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': 'Third heart sound occurs during \nSelect and explain. \nA. Early rapid filling phase of ventricular diastole, B. Late rapid filling phase of ventricular diastole, C. Phase of protodiastole, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 3rd heart sound is due to passive ventricular filling which occurs in early rapid filling phase of ventricular diastole.', 'role': 'assistant'}]