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
All of the following dyes are water soluble except: 
Select and explain. 
A. Metrizamide, B. lohexol, C. Conray 420, D. Myodil
D: Myodil
Answer: D: Myodil 
Explanation: Ans. Myodil