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
[{'content': 'Cobra head sign on IVP is classically seen with \nSelect and explain. \nA. Ureterocele, B. Ectopic ureter, C. Horse shoe kidney, D. Medullary sponge kidney', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cobra\xa0head sign / Adder head\xa0/ Snake appearance.', 'role': 'assistant'}]