Incest Avoidance Can Have Positive Social Advantages by Forcing People

Incest avoidance can have positive social advantages by forcing people to marry outside of their immediate family,thereby:

A) developing a stronger set of relationships within their own family than a wider network of interfamily alliances.
B) creating relationships with people with whom they are likely to cooperate.
C) creating relationships with more people with whom they are likely to become hostile.
D) creating a smaller gene pool.
E) increasing the incidence of recessive traits.