Explanation:

Only statement 3rd is incorrect.

• The Justice Rohini Commission, which has been examining the question of sub-categorisation of OBCs only since 2017, submitted its report and recommendations are not yet made public.

Census and Caste Census In India

• Socio Economic Caste Census (SECC) was conducted for the first time in 1931.

• SECC is meant to canvas every Indian family, both in rural and urban India, and ask about their economic status etc. 

• The Origin of the Census in India goes back to the colonial exercise of 1881.

• Census has evolved and been used by the government, policymakers, academics, and others to capture the Indian population, access resources, map social change, delimitation exercise, etc. 

Hence option 1st is correct.