Why are the 1920s characterized as a decade of major economic change?

I have two possible answers for you. :)

The 1920s was a decade of hope for the Americans.  During this period, the standard of living improved as automobiles, trains and other new modes of affordable transportation gave rise to the suburbs. People were more relaxed and wanted to enjoy life as the economy was.

The 1920's was characterized as a decade of economic prosperity for Americans. Many American citizens invested their money in the Stock Market and were able to make a significant profit off of their investments. The Stock Market success resulted in millions of Americans buying stock on margin. Buying on margin allowed individuals to put 10% of the price of a stock as a down payment while borrowing 90% of the value of the stock from the bank. Banks at this time had thousands, possible millions, of these types of loans available for citizens. This system allowed citizens to have more currency on them, resulting in them spending it on luxury items like stoves, cars, ovens, etc.

Good luck!!

In the 1920s, more Americans than ever had begun living in cities instead of on farms. The nation's wealth doubled at this time, causing people to get swept up in a "consumer society" that helped the economy to grow abundantly.

i believe it would influence their own way of understanding things. it shall be a foundation where they can draw or start an argument.   historians are also  scientists that  have their tools of analysis and expertise to unlock a variety of difficulties such as relationships of man, origin, politics, economy, and culture. based on facts and understanding on these areas, they may shade light to extract ideas and develop options to validate a hypothesis or debunk it.

according to my calculation, the answer is d.