The most important reason why two countries that have the same gdp can have vastly different standards of living is because of

So, current transactions involving assets and property produced in previous periods are not counted in the current GDP. ... Other things not included in the GDP are government social security and welfare payments, current exchanges in stock and bonds, and changes in the values of financial assets.

the answer is:

c. economic output

i’m   sure probably just geuss and see which one you can get right, i’m pretty sure it is the combination of goods and services