A nation's GDP at purchasing power parity (PPP) exchange rates refers to:_____.
a. the value of the GDP divided by the population of the country.
b. the value of all the goods and services produced by a country in a single year.
c. the value of the GDP adjusted for purchasing power.
d. a country's average achievements in health, knowledge, and standard of living.
e. the sum value of all goods and services produced in the country valued at prices prevailing in the United States.