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
A one year old male child presented with poor urinary stream since bih. The investigation of choice for evaluation is: 
Select and explain. 
A. Voiding cystourethrography (VCUG), B. USG bladder, C. Intravenous urography, D. Uroflowmetry
B: USG bladder
Answer: B: USG bladder 
Explanation: Underlying posterior urethral valve (PUV) may be responsible for poor urinary stream that can be diagnosed on USG abdomen