Answer:
B)
a plot by Germany to have Mexico invade the United States
D)
the assassination of the Austrian Archduke caused the U.S. to enter the war
Explanation:
Archduke Franz Ferdinand, heir to the throne of the Austro-Hungarian Empire, and his wife, Sophie, were assassinated by a Bosnian Serb nationalist in Sarajevo in June 28 1914. This caused a war between Austria- Hungary and Serbia a month later. Germany sided with Russia and other countries like France, Belgium, Russia sided with Serbia.
The U.S remained neutral. In 1915, a German submarine sank a British ship and about 128 Americans lost their lives. In March 1916, a German U-boat attacked a French passenger ship which led to the death of many Americans. The U.S. wanted to cut ties with Germany but the Germans promised to warn before attacking passenger ships. The German did not keep to their agreement but continued to sink more passenger ships.
In 1917, the British deciphered a message from German Foreign Minister Arthur Zimmermann to the German minister to Mexico, Heinrich von Eckhart proposing an alliance between Mexico and Germans. The message stated that the Germans would support the Mexicans in regaining the territory that was lost in the Mexican-American War. This lead to the U.S declaration of war against Germany.
