Dadabhai Naoroji was the first to discuss the concept of poverty line. He used the menu for a prisoner to compute the subsistence level cost and then worked out the average expenditure on the basis of prevailing prices. The NCERT textbook credits him with this pioneering work.
Note: The question says during Independent India but Dadabhai Naoroji did this work in the pre-independence era. We have chosen the option that matches the canonical NCERT attribution.