This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Pediatrics
[{'content': 'The most common congenital anomaly of the urinary tract: \nSelect and explain. \nA. Epispadias, B. Hypospadias, C. Exstrophy of bladder, D. Posterior urethral valve', 'role': 'user'}, {'content': 'Answer: B \nExplanation: b. Hypospadias(Ref: Nelson 20/e p 2573-2578)Hypospadias is a urethral opening on the ventral surface of the penile shaft affecting 1 in 250 male newborns.Exstrophy of urinary bladder:It occurs in 1 in 35,000-40,000 births; Male: female ratio is 2:1Severity ranges from simple epispadias (in boys) to cloacal exstrophy. Posterior urethral valve:The most common cause of severe obstructive uropathy in children is posterior urethral valves, affecting 1 in 8,000 boys.', 'role': 'assistant'}]