What was one of the driving forces of the 1929 runaway stock market?
a. corporate earnings
c. buying on credit (margin)
b. foreign purchase of stocks
d. investors holding cash

One of the driving forces of the 1929 runaway stock market was buying on credit (margin).

Explanation:

The stock market crash in 1929 is one of the biggest and worst economic state in history. Though the actual cause for the crash is still debated but few causes have high possibility to have been occurred.With increasing bank credit, people took loans from banks and bought stocks.The concept of 'buying on margin' led to the unafraid situation of debt. Often it was termed as overconfident behavior that led to the economic crash.