Given below two statements : One is labelled as Assertion (A) and other is labelled as Reason (R).
Assertion (A): Non-polar materials do not have any permanent dipole moment.
Reason (R): When a non-polar material is placed in an electric field, the centre of the positive charge distribution of it's individual atom or molecule coincides with the centre of the negative charge distribution.
In the light of above statements, choose the most appropriate answer from the options given below.

We need to evaluate the Assertion and Reason about non-polar materials and dipole moments.

The assertion that non-polar materials do not have any permanent dipole moment is correct. In non-polar materials (like $$O_2$$, $$N_2$$, $$CH_4$$), the centers of positive and negative charge distributions coincide in the absence of an external electric field, resulting in zero permanent dipole moment.

The reason states that when a non-polar material is placed in an electric field, the centre of positive charge distribution coincides with the centre of negative charge distribution; however, this is incorrect. When a non-polar material is placed in an external electric field, the centres of positive and negative charge distributions get separated (they no longer coincide). This separation creates an induced dipole moment. In the absence of an external field, the centres coincide, but the reason specifically refers to the situation under an external field, making it wrong.

Since the assertion is correct but the reason is not, the correct answer is Option C.