Exp) Option d is the correct answer

Article 15 provides that state shall not discriminate against any citizen on grounds only of religion, race, caste, sex or place of birth. The use of word ‘only’ here means that discrimination on other grounds is not prohibited. However, when these conditions are accompanied by some other conditions then state can discriminate. For example, only on basis of caste, state cannot provide discriminatory reservation policy but caste backwardness can become eligible ground for the enactment of discriminatory legislation by the state. The state is permitted to make any special provision for the advancement of any socially and educationally backward classes of citizens or for the scheduled castes and scheduled tribes.