This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'In case of new born the commonest cause of intestinal obstruction is - \nSelect and explain. \nA. Annular pancreas, B. Duodenal Atresia, C. Jejunal atresia, D. Oesophageal atresia', 'role': 'user'}, {'content': "Answer: B \nExplanation: Congenital atresia and stenosis are the commonest cause.\nThe incidence of atresia varies with anatomical site:\nduodenum - 35percent\njejunum - 15percent\nileum - 25percent\xa0\nascending colon - 10percent\nmultiple sites \xa0- 15percent\n\n\nVomiting is bile stained or not, depends on the atresia proximal or distal to ampulla of vater. In 85% of cases the atresia is distal to the ampulla, therefore the vomiting is bilious.\nApproximately 1/3 of newborns with duodenal atresia have associated Down's syndrome.\nThe 'double bubble seen on the air contrast upper GI series is characteristic of duodenal atresia.\nTreatment of choice is - Duodenoduodenostomy", 'role': 'assistant'}]