The correct answer is option 1, Rajya Sabha. Rajya Sabha is the upper house of the Parliament of India and has the power to approve constitutional amendments. The Constitution of India can be amended by a special majority of both houses of Parliament, which includes the Rajya Sabha. The Rajya Sabha consists of members who are elected by the elected members of the State Legislative Assemblies. It is responsible for reviewing and providing its consent to proposed amendments to the constitution. However, it is important to note that the Lok Sabha, the lower house of Parliament, also plays a role in the approval process. Both houses need to approve the amendments for them to become part of the constitution.