This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal Tubular And Obstructive Disorders, Subject name: Pediatrics
[{'content': 'A one year old male child presented with poor urinary stream since bih. The investigation of choice for evaluation is: \nSelect and explain. \nA. Voiding cystourethrography (VCUG), B. USG bladder, C. Intravenous urography, D. Uroflowmetry', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Underlying posterior urethral valve (PUV) may be responsible for poor urinary stream that can be diagnosed on USG abdomen', 'role': 'assistant'}]