The correct answer is D) to determine the price of one country's currency in terms of another country's currency.
The other options of the question were A) promote the arguments supporting free trade. B) promote the use of subsided on foreign goods. C) determine the price of one country's imports in terms of another country's imports.
An exchange rate is used to determine the price of one country's currency in terms of another country's currency.
That is how you can change currency when you visit another country. For instance, if you travel to Mexico City, when you get to the Mexican airport there are many currency booths where you can change your American dollars for Mexican Pesos. The exchange rate is 18 pesos for 1 dollar.
