Although All Societies Have Some Kind of Incest Taboo,the Relationship

Although all societies have some kind of incest taboo,the relationship which is considered incestuous may vary.Concepts of incest seem to be related to a group's definitions of endogamy and exogamy,thus suggesting that incest taboos may help to promote:

A) stability of the family.
B) inbreeding genetic errors.
C) brother-sister marriages.
D) parallel cousin marriages.
E) cross-cousin marriages.