This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urogenital System, Subject name: Radiology
Which of the following is characterized by 'Cobra head deformity'? 
Select and explain. 
A. Cystitis, B. Ureterocele, C. Bladder tumour, D. Posterior urethral valve
B: Ureterocele
Answer: B: Ureterocele 
Explanation: Ans. is 'b' i.e. Ureterocele Adder head or cobra head appearance on excretory urography is typical of Ureterocele. Image: IVP Image: USG