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: Surgery
[{'content': 'Most common congenital anomaly of the upper renal tract is - \nSelect and explain. \nA. Duplication of renal pelvis, B. Duplication of ureter, C. Ectopic ureteric orifice, D. Congenital megaureter', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]