The answer is d. Great moderation.

The term "Great Moderation" refers to a time period from the mid-1980s to 2008 when the economic activity was stable. The macroeconomic stability was mainly seen through the low volatility in inflation rates and real GDP.

The Great Depression was the severe economic recession that took place during the 1930s. The Great Recession was the economic downturn that began in December 2007 and ended in June 2009. Both terms "Great expansion" and "Great economy" do not refer to any period of macroeconomic activity.