Answer:
Scenario C, a state ignoring the nineteenth amendment and passing a law forbidding women to vote, could occur without the supremacy clause.
Explanation:
The supremacy clause, found in Article VI, Clause 2 of the US Constitution, establishes that federal law is the supreme law of the land, and state laws that conflict with federal law are invalid. Without the supremacy clause, states could potentially pass laws that conflict with federal law or the US Constitution and have them be considered valid.
In the given scenario, the nineteenth amendment to the US Constitution grants women the right to vote, but without the supremacy clause, a state could potentially pass a law denying women that right, even though it would conflict with federal law.