This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
In follow up of BPH, most impoant indication of surgery is 
Select and explain. 
A. Prostate size >75gm, B. Single episode of UTI requiring 3 day antibiotics, C. Cannot use medication due to hypeension, D. Bilateral hydronephrosis
D: Bilateral hydronephrosis
Answer: D: Bilateral hydronephrosis 
Explanation: Indications for surgery in BPH are: * Prostatism *Acute retention of urine *Chronic retention of urine with residual urine > 200ml*Complications like hydroureter, hydronephrosis, stone formation, recurrent infections, bladder changes.*HematuriaReference : page 1045 SRB's manual of surgery 5th edition