Step 1: Composition of the Arbitration Council of India (ACI).
The ACI, established under the 2019 Amendment, consists of a Chairperson (a Supreme Court or High Court Judge or an eminent person with legal experience), eminent arbitration practitioners, academicians, and government secretaries from relevant departments.
Step 2: Verification.
While eminent arbitration practitioners, academicians, and government secretaries are included, the Chief Justice of India is not a designated member of the ACI.
Step 3: Conclusion.
Option (a) is correct because the CJI does not hold membership in the ACI.
\[
\boxed{(a)}
\]