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
[{'content': 'A very preterm baby on 30 mL/kg of enteral feeding developed sudden severe abdominal distension with visible bowel loops on day 6 of life. The baby also showed temperature instability and lethargy. s-ray of the abdomen showed poal venous gas. The staging of NEC is: \nSelect and explain. \nA. lb, B. 2a, C. 2b, D. 3a', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c. 2b', 'role': 'assistant'}]