Question

Why did events like the sinking of the Lusitania and discovery of the Zimmerman Note start to change American public opinion on World War I?

a. Americans had been largely neutral, but attacks and threats against civilians, trade, and territory gave credence to the preparedness movement.
b. Most Americans supported the preparedness movement and the expansion of the armed forces until the death tolls began a steady rise.
c. These events killed or threatened Americans and led most to call for an even deeper isolationism that would stop international trade.
d. Despite neutrality, Americans had great sympathy for both sides of the war until these events ended virtually any support for Germany.

Answer 1

A is the answer.

The Americans never wanted to be apart of any war, but now that the Germans were threatening and attacking American civilian boats, support gained quickly.