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': "Rytand's murmur is heard in \nSelect and explain. \nA. Mitral Stenosis, B. PDA, C. Complete AV block, D. Acute rheumatic fever", 'role': 'user'}, {'content': "Answer: C \nExplanation: Rytand's murmur is mid diastolic murmur in complete heart block.", 'role': 'assistant'}]