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: Radiology
Cobra head  deformity is characterstic of 
Select and explain. 
A. Posterior urethral valve, B. Carcinoma of bladder, C. Bladder tumor, D. Ureterocele
D: Ureterocele
Answer: D: Ureterocele 
Explanation: A ureterocele is a congenital abnormality found in the ureter. In this condition the distal ureter balloons at its opening into the bladder,
forming a sac-like pouch. It is most often associated with a duplicated collection system, where two ureters drain their respective kidney instead of one.