How did the U. S. initially react to war breaking out in Europe in 1939? A)The United States began mobilizing troops in anticipation of entering the war later.
B)Congress encouraged the League of Nations to provide assistance.
C)The United States offered Europeans many more opportunities to immigrate.
D)Congress stressed isolationism and wanted to stay neutral
Quartin

D

Explanation:

The US was still a newer country at the time (and still is) so they stayed out of the war until Pearl Harbor bombing as they wanted to have a good image to the rest of the world.

john maynard keynes developed new economic theories in response to the stock market crash of 1929. great depression of the 1930s. first and second world wars. economic boom of the 1950s.