On which of the following grounds is discrimination allowed under Article 15 of the Indian Constitution?

1. 1.Special provisions for advancement of Schedule castes and Scheduled Tribes.
2. 2.Provisions for socially and educationally backward classes regarding admission in private educational institutions.
3. 3.Provisions of free education to children.
4. 4.Reservation ofup to 15% for economically weaker sections in matters regarding appointments.

Select the correct answer using the code given below: