Purchasing power parity is used to compare the gross domestic product between
businesses.
consumers.
stock markets.
countries.

The right answer is between countries.

Purchasing power parity, the PPP, is a calculation of the sum of all goods and services that are produced in a country, compared to the value of another country used as a reference. This measure helps the international monetary fund to establish the size of a country's economy and homogenize world information.

Generally, the economy of the United States is used as a reference, establishing its PPP at 100.

I hope this information can help you.

Purchasing power parity is used to compare the gross domestic product between countries.