Answer:
A. millions of American men showed up at draft boards across the county to volunteer for the war
Explanation:
At first U.S. stayed neutral and viewed World War 1 as a civil war in Europe. However, when Woodrow Wilson became the 28th U.S. president in 1913, he sided with United Kingdom and sent them material aids and this made the Germans angry. In May 7th 1915, there was the Sinking of the RMS Lusitania by a German U-boat. British ocean liner RMS Lusitania, which primarily ferried people and goods across the Atlantic Ocean between the United States and Great Britain. Of the 1,949 people on board, 1,313 died, including 128 Americans. This aroused a wave of indignation in the United States and in 1917, U.S. government decided to enter the war.
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