Question

The quote below was written in the 1920s:

The disaster which was impending was destined to be as bewildering and frightening to the rich and the powerful and the customarily sagacious as to the foolish and unwary holder of fifty shares of margin stock.
--Frederick Lewis Allen

Source: http://xroads.virginia.edu/~hyper/allen/ch13.html

To what event does this quote refer?

the events on Black Tuesday

the programs of the First New Deal

the Dust Bowl

the end of the Dust Bowl