Interested mainly in a small group, country etc

Answer: Option C

One word substitute is Insular.

Fanatic: a person filled with excessive and single-minded zeal, especially for an extreme religious or political cause.
Patriotic: having or expressing devotion to and vigorous support for one's country.
Insular: ignorant of or uninterested in cultures, ideas, or peoples outside one's own experience.
Usurer: a person who lends money at unreasonably high rates of interest.