The relative permittivity has the following units

$$\epsilon = \epsilon_r \epsilon_0$$

Therefore, the relative permittivity is a dimensionless quantity.

Option A is incorrect because the units of farad per meter (F/m) are the units of permittivity.

Option B is incorrect because the units of meter per farad (m/F) are the units of inverse permittivity.

Option C is incorrect because the units of weber per meter (Wb/m) are the units of magnetic flux density.