Which parenting inconsistency is the worst for children's well-being? the parents' household rules unpredictably change. parents are strict in certain areas and permissive in others. each inconsistency is equally "bad" for children. mom is strict and dad is permissive (or vice versa)?

I believe the correct answer is the parents' household rules unpredictably change.

For children's well-being the most important is the consistency in parenting style which is why if the household rules suddenly change in unpredictable matter children will get confused and have a hard time adapting to the new conditions. Apart from that, for the children’s well-being is also important to show love and flexibility in varying their child-rearing strategies to provide the best discipline-environment fit.

i would say b. research typically uses a variety of sources

a is the final ! : )