National Income in India is regularly estimated by:

Planning Commission
Central Statistical Organisation
Ministry of Finance
National Sample Survey Organisation

The correct answer is (b), Central Statistical Organisation (CSO). The CSO is the nodal agency responsible for collecting, compiling, analyzing and disseminating statistical information in India. It is a part of the Ministry of Statistics and Programme Implementation (MoSPI). The CSO regularly estimates the national income of India using a variety of methods, including the production method, the income method, and the expenditure method.

The production method estimates national income by adding up the value of all goods and services produced in the economy in a given year. The income method estimates national income by adding up the incomes of all individuals and businesses in the economy in a given year. The expenditure method estimates national income by adding up the expenditures of all individuals and businesses in the economy in a given year.

The CSO’s estimates of national income are used by the government to formulate economic policies, by businesses to make investment decisions, and by academics to study the Indian economy.

The other options are incorrect. The Planning Commission was a government body that was responsible for planning the economic development of India. It was abolished in 2014. The Ministry of Finance is responsible for the formulation and implementation of the government’s fiscal policy. The National Sample Survey Organisation is responsible for conducting household surveys in India.