The Onset of the Great Depression

The onset of the Great Depression:

A) was not a shock to anyone, since most economists predicted the roaring '20s were bound to end in disaster.
B) caused a disagreement between the Hoover administration and conventional economists because Hoover wanted the government to intervene much more quickly than most others.
C) came as a considerable shock to the conventional wisdom of economics at that time and opened the door for critiques of mainstream thought by economists like John Maynard Keynes.
D) was in 1918 at the end of World War I.