This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
[{'content': 'Dye used in IV cholangiography is \nSelect and explain. \nA. Conray, B. Diansoil, C. Biligraffin, D. Myodil', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Iponoic acid is used in oral cholecystography Biligraffin is used in IV cholangiography Ref: Sabiston 20th edition Pgno :1487', 'role': 'assistant'}]