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: Radiology
[{'content': 'B/L spider leg sign on IVP suggests \nSelect and explain. \nA. Renal stone, B. Polycystic kidney, C. Hypernephroma, D. Hydronephrosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Polycystic Kidney', 'role': 'assistant'}]