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. Ureterocele, C. Bladder tumor, D. Cytitis
B: Ureterocele
Answer: B: Ureterocele 
Explanation: Cobra head (Adder head) ureteric orifice is seen in ureterocoel (mc. cause), stone, tumor and following retrograde catheterization.