GKFix MCQ Question

What is the absolute refractive index of a medium?

• A. The ratio of the speed of light in that medium to the speed of light in vacuum
• B. The ratio of the speed of light in vacuum to the speed of light in that medium
• C. The difference between the speed of light in vacuum and the speed of light in that medium
• D. The sum of the speed of light in vacuum and the speed of light in that medium