The correct answer is: Paper.
Dielectric constant is a measure of how much a material can be polarized by an electric field. Materials with a high dielectric constant are more easily polarized, and therefore have a greater effect on the electric field.
Paper has a relatively low dielectric constant, which means that it is not easily polarized by an electric field. This is because paper is made up of a large number of small, randomly oriented fibers. These fibers are not aligned with the electric field, and therefore do not contribute to the polarization of the material.
Ceramics, oil, and glass all have higher dielectric constants than paper. This is because these materials are made up of larger, more ordered molecules. These molecules are more easily aligned with the electric field, and therefore contribute more to the polarization of the material.
In conclusion, paper has the least value of dielectric constant among the given options.