Final answer:
According to evolutionary theory, stepparents may be less devoted to rearing stepchildren because C) they do not share genetic ties with them.
Step-by-step explanation:
According to evolutionary theory, stepparents may be less devoted to rearing stepchildren because they do not share genetic ties with them (C).
Evolutionary theory suggests that individuals are more likely to invest their time and resources in offspring who carry their own genetic material. Stepparents, on the other hand, are not genetically related to their stepchildren, so they may not have the same level of emotional attachment and investment.