In the 1990s, the Supreme Court Issued a Series of State-Friendly

In the 1990s, the Supreme Court issued a series of state-friendly rulings, including one that struck down most of the Brady Bill, a federal gun control law.This ruling has since been cited in backing the constitutionality of so-called "sanctuary" cities and states, which limit their cooperation with federal immigration enforcement.Why is this the case?

A) The Court ruled that the federal government could not require states to enforce or administer federal laws, such as the Brady Bill.
B) The Court ruled that police powers, which can include immigration enforcement and gun control, are left to the states under the Tenth Amendment.
C) The Court ruled that requiring state and local enforcement of federal laws and policies, without reimbursement, violates the Unfunded Mandates Reform Act.
D) States, under this ruling, were seen as given a broad mandate of independence from the federal government.