Third-Party Attitudes Toward Incest Arise When Individuals Extend Their Own

Third-party attitudes toward incest arise when individuals extend their own aversion to incest to others in the society in which they live, viewing incest by others with disdain. What else is true of this phenomenon?

A) Individuals who grew up with only same-sex siblings have the greatest aversion to incest by other adults.
B) Individuals who grew up only with opposite-sex siblings have the greatest aversion to incest by other adults.
C) Third-party attitudes are genetically coded, so they vary little with the individual's particular history.
D) Third-party aversion is a discredited concept replaced by recent research in evolutionary psychology.