This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New Born Infants, Subject name: Pediatrics
[{'content': 'Most common cause of abdominal mass in neonates is? \nSelect and explain. \nA. Neuroblastoma, B. Multicystic dysplastic kidney, C. Polycystic kidney, D. Umbilical hernia', 'role': 'user'}, {'content': "Answer: B \nExplanation: b. Multicystic dyspiastic kidney(Ref: Nelson's 20/e p 2513)Multicystic dyspiastic kidneyQ is the most common cause of abdominal mass in a neonate.", 'role': 'assistant'}]