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: Medicine
[{'content': 'Regarding S3 heart sound all are true except \nSelect and explain. \nA. May be physiological, B. Due to early diastolic filling of ventricles, C. S3 is heard in acute MR, D. Seen in Conditions associated with increased  preload', 'role': 'user'}, {'content': 'Answer: C \nExplanation: S3 is heard in chronic MR (not in acute MR)', 'role': 'assistant'}]