This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Wide fixed split S2 occurs in \nSelect and explain. \nA. VSD, B. Mitral stenosis, C. ASD, D. Coarctation of aoa', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref Harrison 19 th ed pg 1447 Fixed splitting of S2 , in which the A2 -P2 interval is wide and does not change during the respiratory cycle, occurs in patients with a secundum atrial septal defect.', 'role': 'assistant'}]