Which one among the following Commissions was set up in pursuance of a definite provision under an Article of the Constitution of India?

The Election Commission is the only body among the four that is constituted pursuant to a specific Article of the Constitution. Article 324 vests the power of superintendence, direction and control of elections to Parliament, State Legislatures and the offices of President and Vice‑President in the Election Commission, making it a constitutional body established by the Constitution itself [1]. By contrast, the University Grants Commission is created by Parliament under the University Grants Commission Act, 1956 (a statute) [2]; the National Human Rights Commission was set up by Parliament under the Protection of Human Rights Act, 1993 (a statutory body) [3]; and the Central Vigilance Commission was formed by executive decision on the Santhanam Committee’s recommendation (not by a constitutional Article) [4].

Sources

1. [1] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 43: Election Commission > CHAPTER " Election Commission > p. 419
2. [2] https://www.indiacode.nic.in/bitstream/123456789/1627/1/195603.pdf
3. [3] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 57: National Human Rights Commission > ESTABLISHMENT > p. 473
4. [4] https://humanrightsinitiative.org/publications/police/cvc_cbi_some_developments_a_brief_history.pdf