ANS:B - diamond

The refractive index is highest for diamond. Explanation:

• Refractive index is a measure of how much light is bent or refracted when passing through a medium.
• Diamond has a very high refractive index compared to other materials due to its dense atomic structure and high optical clarity.
• Glass also has a relatively high refractive index, but it is lower than that of diamond.
• Brine (salty water) and kerosene have lower refractive indices compared to both glass and diamond.
• The high refractive index of diamond contributes to its brilliance and sparkling appearance when light enters and reflects within its facets.