The MAIN reason immigrants such as Raczkowski and his brother came to the United States in the early 1900s, according to the excerpt, is:
C. The United States provided more economic opportunities than other countries.
This is evident from Raczkowski's statement that he is doing "ten times better in America than in our country" and that his brother wouldn't return because "there is nothing to return for" and he "could not even earn enough for a loaf of bread" in their home country.