The correct answer is C. both (A) and (B).
The Chief of the Army Staff (COAS) is the professional head of the Indian Army. The COAS is the senior-most officer in the Indian Army and is responsible for the overall command, control, and administration of the Army. The COAS is appointed by the President of India on the advice of the Prime Minister.
The COAS is assisted by the Vice-Chief of the Army Staff (VCOAS), who is the second-in-command of the Army. The VCOAS is responsible for the day-to-day administration of the Army.
The COAS is also assisted by a number of principal staff officers (PSOs), who are responsible for different aspects of the Army’s operations and administration. The PSOs include the Deputy Chief of the Army Staff (DCAS), the Adjutant General (AG), the Quartermaster General (QMG), the Master General of Ordnance (MGO), the Engineer-in-Chief (E-in-C), the Director General of Military Operations (DGMO), and the Director General of Military Intelligence (DDMI).
The PSOs are responsible for providing advice and assistance to the COAS on all matters relating to their respective areas of responsibility. They also play a key role in the planning and execution of the Army’s operations.