This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition, Subject name: Pediatrics
[{'content': 'A neonate presents with bilious vomiting. What is the first investigation __________ \nSelect and explain. \nA. Abdomen X-ray, B. Baby gram, C. CT, D. USG', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In contrast, intestinal malrotation, a congenital anomaly in rotation of the midgut as it forms, presents as intermittent bilious vomiting, usually with significant abdominal distension. Bilious or bile-stained vomiting should be treated as a potential surgical emergency. Reference: GHAI Essential pediatrics, 8th edition Nutrition Chapter', 'role': 'assistant'}]