The correct answer is:<em> relocation to suburbs.</em>
Urbanization brought crowds to the cities, which still makes a lot of people move to the suburbs in order to escape the crowd and maintain a calmer life, but still in a urban envinronment.
Also, suburbs are much cheaper, which makes it also a great option for people who need to work in the cities but can't afford to live next to their work.
The sinking of the Lusitania in 1915 had a very negative effect on the American public opinion of Germany, since it was the Germans who sank the American ship for seemingly no reason.
