Explanation:

- Option 1: Reports of Census of India

- The Census of India collects data on various socio-economic parameters, including employment status, which can serve as an indirect source of unemployment data.

- Option 2: National Sample Survey Organization (NSSO)

- The NSSO conducts surveys on various aspects of India's economy, including employment and unemployment statistics. These surveys are a primary source of detailed unemployment data in India.

- Option 3: DGET

- The Directorate General of Employment and Training (DGET) also gathers data related to employment, including unemployment, through its various programs and initiatives.

- Option 4: All of the above

- This option is correct as all the organizations mentioned contribute to gathering data on unemployment.