This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal Radiology, Subject name: Radiology
[{'content': 'A neonate is brought with history of not having passed meconium. On examination there is no anal opening but a dimple. Investigation of choice would be? \nSelect and explain. \nA. X-ray in erect posture, B. MRI study, C. CT Gastrograffin study, D. Inveogram', 'role': 'user'}, {'content': 'Answer: B \nExplanation: MRI, due to excellent inherent soft tissue contrast,is best to define the relationship of the atretic segment to the levator ani pelvic sling and the integrity of sphincters and their nerve supply (anorectal malformation).', 'role': 'assistant'}]