The correct answer is National Commission for Minorities. While the National Commission for Minorities plays a crucial role in protecting the rights of minorities, it is not a constitutional body. It was established by a parliamentary statute, the National Commission for Minorities Act, 1992. In contrast, the other options are indeed constitutional bodies, meaning their existence and powers are derived directly from the Indian Constitution.

Let's examine each option briefly:

• Attorney General of India: Article 76 of the Constitution of India establishes the office of the Attorney General.
• Special Officer for Linguistic Minorities: Article 350B of the Constitution provides for the appointment of a Special Officer for Linguistic Minorities.
• National Commission for Minorities: This is a statutory body, not a constitutional one, established by an Act of Parliament.
• Comptroller and Auditor General (CAG): Article 148 of the Indian Constitution establishes the office of the CAG.

The key difference lies in the source of their establishment. Constitutional bodies derive their authority directly from the Constitution itself, while statutory bodies are created through laws passed by the Parliament. The National Commission for Minorities, despite its importance, falls under the latter category.