This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': '"Phantom calyx/ Amputed calyx" on IVU is feature of \nSelect and explain. \nA. Tuberculosis, B. Hydronephrosis, C. Bilharziasis, D. UPJ obstruction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .', 'role': 'assistant'}]