D - Invasion of Poland.
The invasion of Poland by Nazi Germany on September 1, 1939, prompted Britain and France to declare war on Germany on September 3, 1939, marking the beginning of World War II.
A - Invasion of Austria
B - Bombing of London
C - Signing a treaty with the Soviet Union
D - Invasion of Poland
1 answer
D - Invasion of Poland.
The invasion of Poland by Nazi Germany on September 1, 1939, prompted Britain and France to declare war on Germany on September 3, 1939, marking the beginning of World War II.