In the excerpt from "Gravity" by Judith Ortiz Cofer, the best example of cultural conflict is:
B. Elenita versus her mother's traditional ideas of fashion.
This is evident in the passage where Elenita's mother insists on buying her a dress for winning an English essay contest, but Elenita feels uncomfortable in the dress and ends up changing into a more plain outfit at school. This highlights a clash between Elenita's preference for simplicity and her mother's inclination towards more traditional, perhaps fancier, attire. The conflict between Elenita's personal style choices and her mother's expectations represents a cultural clash related to fashion and self-expression.