<u> B) The sinking of the Lusitania </u>
Before the sinking of Lusitania occurred, the U.S. had kept a neutral position regarding WW I. However, the event, caused by Germany, started to turn Americans public opinion against Germany. And two years later the U.S. decided to enter WWI on the side of the Allies.
Lusitania was a 32,000-ton ship that was carrying about 173 tons of munitions for Britain for the war ongoing. On May 7, 1915, it was hit by a torpedo sent by Germans. The result was devastating: More than 1000 people died in the sinking. Though afterward, Germany apologized, it later continued to cause the sinking of several ships more, and in April 1917 the U.S. entered the war.