Why did buying on margin contribute to the Great Depression? (Select all that apply)

A. Buying on margin caused stocks to be valued at a price higher than their actual value.B. Stocks became devalued when buying on margin allowed stocks to be purchased at below market value. C. Investor groups could buy stocks even if the group could not cover the capital for the investment. D. The low investment capital to purchase a stock led to many investors losing a fortune.