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 decennial census of India, as well as other demographic and socio-economic surveys.
The NITI Aayog is a policy think tank of the Government of India. It was set up in January 2015 by the prime minister Narendra Modi, in pursuance of the recommendations of the 14th Finance Commission. The NITI Aayog is not responsible for conducting the census.
The National Statistical Office is a wing of the Ministry of Statistics and Programme Implementation, Government of India. It is responsible for collecting, compiling, analyzing and disseminating statistical information on the social, economic and demographic aspects of the country. The National Statistical Office is not responsible for conducting the census.
The Ministry of Home Affairs is a ministry of the Government of India that is responsible for the maintenance of internal security, law and order, and border management. The Ministry of Home Affairs is not responsible for conducting the census.