Which of the following material has least value of dielectric constant ?

This question asks about the dielectric constant, which is a material's ability to store electrical energy in an electric field.
A lower dielectric constant means the material stores less energy.

Let's look at the options:
* Ceramics generally have a relatively high dielectric constant.
* Oil has a lower dielectric constant compared to ceramics and glass.
* Glass also has a relatively high dielectric constant.
* Paper has a dielectric constant higher than oil.

Therefore, oil has the least value of dielectric constant compared to the other materials listed.
So the answer is Option B: Oil