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 cause of hydronephrosis in children 
Select and explain. 
A. Ureterocoele, B. Ureteric stricture, C. Watermelon prostate, D. Congenital PUJ obstruction
D: Congenital PUJ obstruction
Answer: D: Congenital PUJ obstruction 
Explanation: Congenital PUJ obstruction is MCC for hydronephrosis in children.