Hm, I think the question here calls for "d", although d would be better defined as a focus on one's own culture, and ignoring other cultures, or seeing other cultures through the lense of own culture.
In a way, prejudice could be a good lead, but only if it said "prejudice towards all other cultures" which is not really feasible (one can't know all other cultures).
so, still, d is best, although there can be ethnocentrism without feeling superior