1. Permanent Chairman of Chiefs of Staff Committee: This is correct. The CDS is designated as the Permanent Chairman of the Chiefs of Staff Committee (COSC), which includes the chiefs of the Army, Navy, and Air Force. 2. Exercise military command over the three Service Chiefs: This is incorrect. The CDS does not have direct operational command authority over the three service chiefs. The service chiefs continue to exercise operational command over their respective services. The CDS acts as a coordinator and advisor, promoting jointness and integration among the services. 3. Principal Military Advisor to Defence Minister on all tri-service matters: This is correct. The CDS acts as the single-point military advisor to the Defence Minister on matters related to all three services. This ensures streamlined and integrated military advice to the political leadership.   4. Additional Information - The creation of the post of the Chief of Defence Staff was recommended by these committees: Group of Ministers (2001), Naresh Chandra Committee and D.B. Shekatkar Committee.  Therefore, the correct statements are 1 and 3.