Answer:
The correct answer to the following question is option D) Key economic indicators such as GDP, to measure the economic progress .
Step-by-step explanation:
U.S.A economy can be said to be world's highly developed mixed economy, which is the largest economy in the world when seen by nominal GDP ( gross domestic product ) and second when seen through the purchasing power parity . The U.S economy can be measured by GDP, which represents all the goods that are produced in the economy in a given period. If in some situation the GDP rate turns negative , it would mean that the economy has enter in to a period of recession.