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': 'Most common type of atrial septal defect is ___________ \nSelect and explain. \nA. Ostium primum, B. Ostium secondum, C. Endocardial cushion defect, D. Endocardial hyperophy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most common type of ASD is ostium secundum. Ref : Ghai essential of pediatrics, eighth edition, p.no:413', 'role': 'assistant'}]