How Is the Career of Paul an Example of the "Cosmopolitan

How is the career of Paul an example of the "cosmopolitan" nature of the Roman Empire?

A) He limited his proselytizing to urban areas.
B) He only converted Romans to Christianity.
C) He refused to debase himself by using anything Roman.
D) He was able to use the benefits of Roman citizenship, roads, and cities to spread Christianity.
E) He found that both Jews and Christians readily accepted his views of Jesus as the messiah.