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: Anatomy
The narrowest valvular pa of ureter is: 
Select and explain. 
A. At pelvic brim, B. At ischial spine, C. Pelvic ureteric junction, D. At the entry of bladder
D: At the entry of bladder
Answer: D: At the entry of bladder 
Explanation: At the entry of bladder