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: 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: An X-ray film of the abdomen is obtained 12-24 hours after birth, with baby being kept in an inverted position.', 'role': 'assistant'}]