This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney and ureter, Subject name: Surgery
Retrocaval ureter occurs due to persistence of: 
Select and explain. 
A. Azygous vein, B. Hemiazygous, C. Anterior cardinal vein, D. Posterior cardinal vein
D: Posterior cardinal vein
Answer: D: Posterior cardinal vein 
Explanation: Retrocaval Ureter- Aka Circumcaval ureter- Abnormal development of IVC causes ureter to pass behind IVC and to take U turn before draining to bladder.- Abnormal persistence of right posterior subcardinal vein Clinical features- Signs & symptoms of ureteric obstruction Diagnosis- MRI is IOC to a delineate anatomy clearly and non-invasively- IVP "Reverse J" "Fish Hook" Or "Shepherd Crook "deformity Treatment - Relocation ureteroureterostomy