Let's analyze each statement: a. Zonal Councils are the constitutional bodies. (Incorrect - Zonal Councils are statutory bodies established under the States Reorganisation Act, 1956). b. The Prime Minister acts as the Chairman of all Zonal Councils. (Incorrect - The Union Home Minister acts as the Chairman of each Zonal Council). c. Each Chief Minister acts as the Vice-Chairman of the Zonal Council by rotation. (Correct - A Chief Minister from one of the states in the zone holds the office of Vice-Chairman for one year at a time by rotation). d. Joint meetings of two or more Zonal Councils are presided over by the Union Home Minister. (Correct - The Union Home Minister presides over joint meetings).