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: Surgery
Treatment of choice in a patient with a staghorn calculus with mild hydronephrosis? 
Select and explain. 
A. ESWL, B. PCNL, C. RIRS, D. Open surgery
B: PCNL
Answer: B: PCNL 
Explanation: Answer- B. PCNLPCNL is the best answer as the patient has hydronephrosis and in an obstructed system ESWL is not useful as stone fragments don't get cleared.