This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Stomach and Intestines, Subject name: Pediatrics
[{'content': '3 month infants with abdominal palpable mass & non bilious vomiting - \nSelect and explain. \nA. Hypertrophic biliary stenosis, B. Hypertrophic pyloric stenosis, C. Tracheoesophageal fistula, D. Duodenal atresia', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Hypertrophic pyloric stenosis Hypertophic pyloric stenosiso Most common cause of nonbilious vomiting is Hypertrophic pyloric stenosis,o Male > female.o Vomiting starts with 3 week of age.o Palpable mass is seen in epigastric region,o Visible peristalsis is seen soon after feeding,o Confirmed by USG abdomen,o Contrast study shows :Shoulder signDouble tract sign.o Treatment surgery = Ramstedt procedure.", 'role': 'assistant'}]