This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastro Intestinal System, Subject name: Pediatrics
A 5-day-old term male neonate presents with delayed passage of meconium, abdominal distension and bilious vomiting. Barium enema and intestinal biopsy findings are shown below. What is the diagnosis? 
Select and explain. 
A. Congenital aganglionic megacolon, B. Hypertrophic pyloric stenosis, C. Cystic fibrosis, D. Intestinal malrotation
A: Congenital aganglionic megacolon
Answer: A: Congenital aganglionic megacolon 
Explanation: a. Congenital aganglionic megacolonBa enema shows narrow distal segment with dilated proximal segment of intestineIntestinal biopsy shows hypertrophied nerve bundles between muscular layer & submucosa