Isotropic Materials:
Isotropic materials are materials that have the same physical properties in all directions. This means that the properties of the material, such as electrical conductivity, thermal conductivity, and mechanical properties, are independent of the direction in which they are measured. Isotropic materials exhibit the same behavior regardless of the orientation of the applied field or force.

Permittivity:
Permittivity is a measure of how easily a material can be polarized in response to an electric field. It is a property that determines the electric flux density produced by an electric field in a material. In isotropic materials, the permittivity is independent of the direction of the applied electric field. This means that the material will have the same response to an electric field regardless of its orientation. Therefore, the permittivity of an isotropic material will be independent of the direction.

Permeability:
Permeability is a measure of the ability of a material to support the formation of a magnetic field within itself. It is a property that determines the magnetic flux density produced by a magnetic field in a material. In isotropic materials, the permeability is also independent of the direction of the applied magnetic field. This means that the material will have the same response to a magnetic field regardless of its orientation. Therefore, the permeability of an isotropic material will be independent of the direction.

Polarization:
Polarization is the process of aligning the electric dipole moments in a material in response to an applied electric field. The polarization of a material depends on the direction of the applied electric field. In isotropic materials, the polarization will not be independent of the direction. The material will exhibit the same polarization behavior in all directions.

Polarizability:
Polarizability is a measure of how easily a material can be polarized in response to an applied electric field. It quantifies the ability of a material to induce an electric dipole moment per unit volume in the presence of an electric field. In isotropic materials, the polarizability will also not be independent of the direction. The material will have the same polarizability behavior in all directions.

Conclusion:
In isotropic materials, both the permittivity and permeability will be independent of the direction. The polarization and polarizability, on the other hand, will depend on the direction of the applied electric field. Therefore, the correct answer is option 'A' - permittivity.

Permettivity