Question

what caused great britain and france to declare war on germany in 1939?
the appeasement policy
the invasion of poland
the nonaggression pact
the surrender of poland

Explanation:

Great Britain and France had guaranteed Polish independence. When Germany invaded Poland on September 1, 1939, they issued ultimatums for Germany to withdraw, which were ignored. This led to their declaration of war on Germany on September 3, 1939. Appeasement was a prior policy that failed to prevent aggression, the nonaggression pact was between Germany and the USSR, and Poland's surrender happened after the declaration of war.

Answer:

the invasion of Poland