Question

The key factor in the decision of the U.S. to enter World War I was

a. A long-standing friendship with Great Britain
b. American prejudice against German immigrants
c. The political ambition of Woodrow Wilson
d. Germany's resumption of unrestricted submarine warfare against the U.S.

Answer 1

The key factor in the decision of the U.S. to enter World War I was "d. Germany's resumption of unrestricted submarine warfare against the U.S.," since this led to the sinking of the Lusitania, which had many US citizens on board.