Answer:
A but if multiple choice then A and D
Explanation:
I think that maybe people are saying different answers because there might have been many such laws. I will mention one example: the Diversity Visa Immigration: it means that people from Eastern Europe have a higher change of obtaining a visa due to a smaller population in the US than the western European Countries.
If I remember it correctly the right answer is B. Religious traditions .
Most isolationists felt that there was no need for americans to feel threatened by developments in Europe and Asia because the vast pacific and atlantic oceans insulated the country from troubles in those regions, and the United States had formed friendly alliances with all the other nations in the Western hemisphere.