This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Digestive System Disorders, Subject name: Pediatrics
The time usually taken for air to reach the descending colon after birth in a normal infant is: 
Select and explain. 
A. l-2hrs, B. 3-4 hrs, C. 5-6 hrs, D. 8-9 hrs
D: 8-9 hrs
Answer: D: 8-9 hrs 
Explanation: Ans. (d) 8-9 hrs* Since there is no gas in the abdomen of a new born baby, in case we are investigating a baby with ano- rectal malformations, the X-Ray to be done shall be an INVERTOGRAM and should be done after 8 hours as that would the time taken for air to reach the descending colon and performing the X ray shall be fruitful.