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: Radiology
[{'content': 'Radiological finding in ileal atresia : \nSelect and explain. \nA. Microcolon on Ba enema, B. Double bubble sign, C. Coil spring appearance in Ba-Enema, D. All', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Microcolon on Ba enema', 'role': 'assistant'}]