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': 'This sound is produced during the closure of the semilunar valves. \nSelect and explain. \nA. lubb, B. dupp, C. lubb dupp, D. lubb duppshhh', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B:\xa0The second heart sound can be represented by\xa0dupp. It occurs at the beginning of ventricular diastole and results from the closure of the semilunar valves.\nA:\xa0The first heart sound can be represented by the syllable\xa0lubb. It occurs at the beginning of ventricular systole and results from closure of the AV valves.', 'role': 'assistant'}]