This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
[{'content': 'All of the following hea sounds occur sholy aftei S2except- \nSelect and explain. \nA. Opening snap, B. Pericardial knock, C. Ejection click, D. Tumor plop', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ejection click occurs due to semilunar valve opening with high pressure. Eg: AS, PS. It is high pitched. Opening snap : 80ms after S2 Pericardial knock : 100 ms after S2 Ref: Harrison 20th edition 1445', 'role': 'assistant'}]