Direction: Question consists of two statements, one labeled as the 'Assertion (A)' and the other as 'Reason (R)'. Examine these two statements carefully and select the answer to this question using the codes given below:Assertion (A): The velocity of light in any medium is slower than that of vacuum.Reason (R): The dielectric constant of the vacuum is unity and is lesser than that of any other medium.

• A. Both A and R are individually true and R is the correct explanation of A
• B. Both A and R are individually true but R is not the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true