This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
[{'content': 'A new born girl not passed meconium for 48 hrs, has abdominal distention and vomiting, Initial investigation of choice would be \nSelect and explain. \nA. Manometry, B. Genotyping for cystic fibrosis, C. Lower GI contrast study, D. Serum trypsin immunoblot', 'role': 'user'}, {'content': 'Answer: C \nExplanation: bowel obstruction with an absent caecal gas shadow in ileocolic cases. A soft tissue opacity is often visible in children. A barium enema may be used to diagnose the presence of an ileocolic intussusception (the claw sign) Ref: Bailey & Love&;s Sho Practice of Surgery,E25,Page-1196', 'role': 'assistant'}]