This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney Stones & Renal Tubular Acidosis, Subject name: Medicine
[{'content': 'Best for management of a 3 cm stone in renal pelvis without evidence of hydronephrosis is? \nSelect and explain. \nA. ESWL, B. PCNL, C. Antegrade Pyeloplasty, D. Retrograde pyeloplasty', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ESWL- done for stone less than 2.5 cm size PCNL-if stone is > 2.5 cm will treat by PCNL Most common kidney stone =calcium oxalate Etiology=idiopathic hypercalciuria', 'role': 'assistant'}]