Among the listed bodies, only the Inter-State Council is established by the Constitution of India. The others are based on statutory or executive provisions.

✅ I. Inter-State Council – Correct

• Established under Article 263 of the Constitution to facilitate Centre-State coordination.

❌ II. National Security Council – Incorrect

• Formed in 1998 by an executive order, not mentioned in the Constitution.

❌ III. Zonal Councils – Incorrect

• Established under the States Reorganisation Act, 1956, a statutory but non-constitutional body.