Correct Answer: (d) Non -organized sector
Solution:Non-organized sector is one of the main problems in calculating National Income in India. Quite often, the unorganized sector, i.e., small scale units, agriculture sector, etc., do not keep proper records relating to workers and other factors of production for various reasons. Other main problems in calculating National Income in India includes: Inadequate and unreliable data, problem of double counting, non-monetized sector, black money transactions, illegal income, problem of transfer payments (old age pensions, scholarships, etc.), problem of definition of National Income, etc.