This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Contrast Agents, Subject name: Radiology
Iodine paicle ratio for Ionic dimer is 
Select and explain. 
A. 6:01, B. 3:02, C. 6:02, D. 2:06
C: 6:02
Answer: C: 6:02 
Explanation: Iodine paicles ratio: I: P Ionic monomer 3: 2 High osmolar Low Osmolar Ionic dimer 6: 2 Nonionic monomer 3: 1 Low osmolar Non-ionic dimer 6: 1 Iso-osmolar to plasma(290-300mosm)