National income calculation and definition

National income is defined as the money value of final goods and services produced within a country's borders during a given period, typically one year. This is the GDP (Gross Domestic Product) approach. Option (a) is incorrect because it refers to Gross National Income (GNI), which includes income earned by nationals regardless of location. Option (b) is incorrect as the sum of consumption and investment is a use of income, not the definition of national income itself. Option (c) is incorrect as personal income excludes certain components like retained corporate earnings and government income. The correct definition focuses on final goods and services (not intermediate goods) produced, measured at market value. > National Income Definition: National income equals the market value of all final goods and services produced within a country's borders during a specific period. Answer: (d).