Which of the Following Was LEAST Likely to Have Contributed

Which of the following was LEAST likely to have contributed to the Jewish diaspora maintaining a distinct identity within host communities in Europe and elsewhere?

A) Being made to live in ghettos, walled off from others
B) Toasting to "New year in Jerusalem" on important holidays like Yom Kippur and Passover
C) Evolving new languages like Yiddish and Ladino that only some Jewish communities spoke or understood
D) Exposure to religious teaching that a Messiah would come and re-establish a Jewish kingdom