Select the correct answer:
 
The refractive index of diamond is \(2.42\). What does this statement mean?
 
Consider,
\(\mu\) - Absolute refractive index
\(c\) - Speed of light in vacuum
\(v_m\) - Speed of light in medium
 
Then,
If the refractive index of diamond is \(2.42\), then the speed of light in diamond is,