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
A neonate is brought with history of not having passed meconium on examination there is no anal opening but a dimple. Investigation of choice is: 
Select and explain. 
A. X-ray erect posture, B. X-ray supine posture, C. Gastrograffin study, D. Inveogram
D: Inveogram
Answer: D: Inveogram 
Explanation: Ans. Inveogram