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: Pediatrics
[{'content': 'Obstruction in pulmonary stenosis may occur at the following sites ___________ \nSelect and explain. \nA. Supravalvular, B. Valvular, C. Subvalvular, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In PS obstruction can be supravalvular,valvular, subvalvular. Ref : Ghai essential of pediatrics eighth edition, p.no:433', 'role': 'assistant'}]