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
Dye used in IV cholangiography is: 
Select and explain. 
A. Dianosil, B. Conray, C. Billigraffin, D. Myodil
C: Billigraffin
Answer: C: Billigraffin 
Explanation: Ans. Billigraffin