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': 'One of the following will always present with Bilious vomiting - \nSelect and explain. \nA. Pyloric stenosis, B. Esophageal atresia, C. Atresia of the 3rd part of the duodenum, D. Malrotation of the gut', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The CBD opens into the 2nd part of duodenum. So obstructions which are proximal to it like pyloric stenosis & esophageal atresia would not have bile in their associated vomits.\nBilious vomiting would only occur if the obstruction is distal to CBD opening.\nAtresia of the 3rd part of duodenum would always produce bilious vomiting.\nMalrotation of the gut is a broad entity and may manifest clinically in several different ways. The vomiting may be bilious or nonbilious.', 'role': 'assistant'}]