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
Most common congenital anomaly of the upper renal tract is - 
Select and explain. 
A. Duplication of renal pelvis, B. Duplication of ureter, C. Ectopic ureteric orifice, D. Congenital megaureter
A: Duplication of renal pelvis
Answer: A: Duplication of renal pelvis 
Explanation: None