This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Necrotising enterocolitis, Subject name: Pediatrics
Indication for surgery in Necrotizing Enterocolitis is? 
Select and explain. 
A. Pneumatosis intestinalis- Stage IIA of NEC, B. Pneumoperitoneum- Stage IIIB of NEC, C. Poal Vein gas- Stage IIB of NEC, D. Peritonitis- Stage IIIA of NEC
B: Pneumoperitoneum- Stage IIIB of NEC
Answer: B: Pneumoperitoneum- Stage IIIB of NEC 
Explanation: Pneumoperitoneum -NEC stage 3b- intestinal perforation occurs. Treatment includes suppoive care along with surgery. Modified Bell's Staging Criteria: