Question

In the 1800s, what was the most important motivation for both “old” and “new” immigrants to settle in ethnic neighborhoods?

Answer 1

The answer is common language.  It could also be common culture since they are all from the ethnic race, it promotes a sense of community where people feel safe knowing that they are among their fellow countrymen in a new land.  

Answer 2

Answer;

C. a common language.

In the 1800s, an important motivation for both "old" and "new" immigrants to settle in ethnic neighborhoods was a common language.

Explanation;

The old immigrants came from the northern or western Europe while the new immigrants came from southern or eastern Europe.

Old immigrants were protestant while the new immigrants were Catholic , Orthodox or Jewish.