This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastro Intestinal System, Subject name: Pediatrics
[{'content': 'X-ray detect congenital anorectal malformation at: \nSelect and explain. \nA. Immediately after birth, B. 24-48 hours, C. 48 - 72 hours, D. After 72 hours', 'role': 'user'}, {'content': 'Answer: B \nExplanation: (24-48 hours) (178-G) (1286-87-Nelson 17,h) (152-Ghai 7th)Anorectal malformation* AT birth the bowel is not distented; there fore clinical and radiologic evaluations are not reliable during the first 16-24 hour of life.* A cross table Lateral film with the patient in prone (inverted) position taken after 16-24 hours of life is valuable for determining the position of rectal pouch.* During the first 24 hour of life, all these patients need renal and bladder ultrasound evaluation to identify an obstructive uropathy.', 'role': 'assistant'}]