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 secondom, C. Endocardial cushion defect, D. Endocardial hypertrophy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (Ostium secondum) (400-G) (401-Ghai 7th)Atrial septal defect - ostium secondum type is 10 times more common than the endocardial cushion defrct.* Ostium secondum - generally anatomically located at the fossa ovalis superior or posterior to the fossa - ovalis.* Ostium primum - is situated inferior to the fossa-ovalis* CHF, Infective endocarditis is rare* The ideal age of operation is between 2-5 years.', 'role': 'assistant'}]