Examine this timeline:

August 23, 1939 — Germany and the Soviet Union sign a treaty to not attack one another.
September 1, 1939 — Germany invades Poland.
September 27, 1940 — Germany and Japan sign a pact stating they will not attack each other and will provide military assistance if attacked by a nation not already involved in the war.
December 17, 1940 — The United States promises to provide European allies with military equipment through the Lease-Lend Act.
December 7, 1941 — Japanese bombers destroy large portions of the U.S. Navy at Pearl Harbor.
December 7, 1941 — Japan officially declares war on the United States.
December 8, 1941 — The United States declares war on Japan.
December 11, 1941 — Germany declares war on the United States.
December 11, 1941 — The United States declares war on Germany.
Based on the information in the timeline, which causal explanation for the German actions in World War II is accurate?
A. Germany's pact with Japan caused it to declare war on the United States.
B. Germany declared war on the United States because it was sending military aid to its enemies.
C. Germany signed the pact with Japan in response to the United States signing of the Lend-Lease Act.
D. Germany's invasion of Poland caused Japan and the Soviet Union to sign an agreement to not attack one another.

When making an analysis of the information provided in the timeline, it becomes clear that Germany acted how it did because of its alliance with Japan, which consisted of a pact that stated that military assistance was to be supplied in the events of an attack on one of the parts concerned in said arrangement by a nation not involved in the war. This ultimately led to Germany to declare war on the United States.