The correct option is A Constituencies for the weaker sections
Reserved Constituencies are the constituencies in which people only belonging to the scheduled tribes and scheduled castes who can contest the election. In India, there are certain numbers of university positions and political positions are organized for specified groups of people including Scheduled Castes, Scheduled Tribes, women and so on. Hence, Option A is correct. The rest of the clauses do not fit in this definition, hence, incorrect.