What would be the best heading based on the list below?
-unrestricted submarine warfare zimmerman telegram sinking of u.s.
-ships the lusitania responses reasons europe went to war reasons europe went to war reasons the u.s.
-entered world war i reasons the u.s.
-entered world war i reasons for the spanish-american war reasons for the spanish-american war reasons the u.s.
-stayed neutral during world war i