Which of the following is a "Source" for data on unemployment?

All of the above

There are three sources of data on unemployment : Reports of Census of India, National Statistical Office’s Reports of Employment and Unemployment Situation, Annual Reports of Periodic Labour Force Survey, and Directorate General of Employment and Training data of Registration with Employment Exchanges. Though they provide different estimates of unemployment, they do provide us with the attributes of the unemployed and the variety of unemployment prevailing in our country.