The answer is letter C. Southern and Eastern Europe.
For three centuries, immigrants continued flocking in from the northern and western part of Europe yet, in decreasing numbers. Thereafter, in 1880s, the increasing number of immigrants came from the East and from the South of European countries, in Canada and Latin America too. In the year 1910, the Eastern and Southern immigrants made up to 70% but dropped off in 1914 because of the war and the imposed restrictions in the 1920s.