National Income estimates in India are prepared by

Explanation:

The Central Statistical Organisation (CSO) is the nodal statistical organization of the country.
It was set up in 1950 under the Ministry of Statistics and Programme Implementation.
The CSO provides the data on national income, which is used in the preparation of the National Accounts Statistics.
The data is compiled from various sources such as administrative records, surveys, censuses, etc.

Final answer :

Hence, the correct option is D. Central Statistical Organisation.