Choice "d" is correct. Real GDP per capita is real GDP divided by population. Real GDP per capita is

typically used to compare standards of living across countries or across time. By dividing real GDP by

population, this measure adjusts for differences in the size of countries and for differences in

population over time.

Choice "a" is incorrect. Government spending is not a measure of the standard of living of a country.

Choice "b" is incorrect. Countries with larger populations tend to have higher levels of real GDP. This

however does not mean they have a higher standard of living. To adjust for differences in population,

real GDP per capita is typically used to compare standards of living, not real GDP.

Choice "c" is incorrect. Real consumption expenditures are only a part of real GDP and thus do not

measure all economic activity. Furthermore, real consumption expenditures do not adjust for

differences in population. It is therefore not used as a measure of the standard of living.