Q.Net Factor Income from Abroad (NFIA) is correctly defined as:

NFIA is the net inflow of factor income a country's own residents earn from the rest of the world — what they earn abroad, minus what non-residents earn within the country. …

NFIA links the domestic concept (GDP) to the national concept (GNP): $GNP = GDP + NFIA$.

By definition, $NFIA = \text{Factor income received by residents from abroad} - \text{Factor income paid to non-residents within the country}$ — option (a).

Option (b) simply reverses the sign, which would make NFIA negative whenever a country's residents earn more abroad than non-residents earn domestically — the opposite of the correct relationship. Option (c) is incorrect because GNP minus NNP equals Depreciation, not NFIA. Option (d) is also incorrect — GDP plus Consump …