Write the names of the three scholars who calculate national income before independence.

In the pre Independence era, several estimates of national income were made by Dadabhai Naoroji (1868), V.K.R.V. Rao (1925-29) and R.C. Desai (1931-40). Among these, the estimates of Naoroji have computed the value of the output raised by the agricultural sector and then added some portion of the income earned by the non-agricultural sector. But these estimates have no scientific basis of its own.