The correct answer is: a) Office of the Registrar General & Census Commissioner.
The Office of the Registrar General & Census Commissioner is a statutory body under the Ministry of Home Affairs, Government of India. It is responsible for conducting the Census of India, which is a decennial exercise to collect and compile demographic, social, economic and housing data of the country. The Census is the largest peacetime exercise in the world and is used to plan for the development of the country.
The National Statistical Commission is an independent body constituted by the Government of India to advise on statistical matters. It is not responsible for conducting the Census.
The Planning Commission was an Indian government planning body that was dissolved in 2014. It was responsible for formulating India’s Five-Year Plans. It was not responsible for conducting the Census.
The Ministry of Home Affairs is a ministry of the Government of India that is responsible for internal security, law and order, and border management. It is not responsible for conducting the Census.