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
Failure to pass meconium within 48 hrs of bih in a newborn with no obvious external abnormality should lead to the suspicion of- 
Select and explain. 
A. Anal atresia, B. Congenital pouch colon, C. Congenital aganglinosis, D. Meconium ileus
C: Congenital aganglinosis
Answer: C: Congenital aganglinosis 
Explanation: Ans. is 'c' i.e., Congenital aganglinosis o Read what Nelson says about Hirschsprung's disease (Congenital aganglinosis). o "Ninety nine percent of full term infants pass meconium within 48hrs of bih. Hirschsprung disease should be suspected in any full term infant with delayed passage of stool".