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: Radiology
The most impoant investigation for posterior urethral value is: 
Select and explain. 
A. Urethroscopy, B. IVP, C. Retrograde cystogram, D. Micturating cystogram
D: Micturating cystogram
Answer: D: Micturating cystogram 
Explanation: Ans. Micturating cystogram