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: Pediatrics
Posterior urethral valve is diagnosed on micturating cystometrogram by : 
Select and explain. 
A. Dilatation of posterior urethra, B. Bladder neck contracture, C. Vesico-Ureteric reflex, D. Bladder wall hypertrophy
A: Dilatation of posterior urethra
Answer: A: Dilatation of posterior urethra 
Explanation: Micturating cystourethrogram findings :

Dilation of prostatic urethra.
Transverse linear filling defect corresponding to the valves.