Which Is an Example of How Diversity Is Reinforced by Federalism

Which is an example of how diversity is reinforced by federalism?

A) The passage of a conservative economic policy in Oklahoma and a liberal environmental policy in California.
B) Imposing strict handgun laws at the federal level for all states to adopt and enforce.
C) Implementing affirmative action programs in hiring and admissions to colleges and universities.
D) Giving preferential treatment to historically oppressed classes of people in public accommodations.