Option 3: (A) - (III), (B) - (I), (C) - (IV), (D) - (II) -> Let's match each concept correctly:
(A) Non-monetary exchanges refer to economic activities that don't involve money transactions. Domestic services by housewives (III) are a perfect example - they have economic value but aren't captured in GDP since no money is exchanged.
(B) Externalities are spillover effects of economic activities on third parties. They can be positive (I) like education benefiting society, or negative like pollution harming the environment.
(C) Per capita income is calculated as Total income/Population (IV). It represents the average income per person in an economy.
(D) GDP deflator is a Price Index (II) used to convert nominal GDP to real GDP by removing the effect of inflation. It measures the price level of all domestically produced goods and services.
Therefore, the correct matching is: (A)-(III), (B)-(I), (C)-(IV), (D)-(II) -> correct