Explanation:

- Option 1: NNPFC = GNPFC – Depreciation

- This suggests that Net National Product at Factor Cost (NNPFC) is derived by subtracting depreciation from Gross National Product at Factor Cost (GNPFC).

- Option 2: NNPFC = NNPMP + Economic subsidy – Indirect taxes

- Net National Product at Factor Cost can also be obtained by taking Net National Product at Market Price (NNPMP) and adjusting for economic subsidies and indirect taxes.

- Option 3: NNPFC = NDPMP + Net factor income from abroad

- Here, NNPFC is calculated by adding net factor income from abroad to Net Domestic Product at Market Price (NDPMP).

- Option 4: All of these

- All three methods provide valid ways to calculate NNPFC because they account for income adjustments, depreciation, and net foreign income.

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