Who is the Chairman of the Chiefs of Staff Committee?

Who is the Chairman of the Chiefs of Staff Committee?

The Chief of Army Staff
The Chief of Naval Staff
The Chief of Air Staff
The member who has been the longest on the Committee
This question was previously asked in
UPSC CDS-2 – 2016
Based on the options provided and the likely context before the creation of the permanent CDS role, the correct answer is D.
Prior to the creation of the Chief of Defence Staff (CDS) position as the permanent Chairman of the Chiefs of Staff Committee (COSC) in 2020, the Chairman of the COSC was traditionally the longest-serving chief among the three service chiefs (Chief of Army Staff, Chief of Naval Staff, and Chief of Air Staff). As the options do not include CDS, the question likely refers to this previous arrangement.
The Chiefs of Staff Committee comprises the three service chiefs and the CDS. The CDS serves as the permanent Chairman. Before the CDS, the rotating chairmanship based on seniority aimed to coordinate among the three services.