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: Anatomy
Locate the renal stone with pain radiating to medial side of thigh and perineum due to slipping of stone in males 
Select and explain. 
A. At pelvic brim, B. Intramural opening of ureter, C. Junction of ureter and renal pelvis, D. At crossing of gonadal vessels and ureter
A: At pelvic brim
Answer: A: At pelvic brim 
Explanation: The clinician is able to judge the position of the stone by the history of pain - Ref : S. Das manual, 4/e p408