D) sustained period during which the nation's total output of goods and services increases.
Explanation:
Economic growth occurs when a country can increase the production and marketing of goods and services produced in the various sectors of its economy over a long and sustainable manner. The main indicator that measures economic growth is GDP. Thus, when a country's GDP is positive, it means that the country is experiencing economic growth. During economic growth the country becomes more prosperous and wealthier, the employment rate tends to decrease and society as a whole wins.