The correct answer to this open question is the following.
Althought there are no options attached, we can say the following.
When Congress intends to exclusively control a subject where the U.S. Constitution allows for both states and the federal government to act, courts will use the doctrine of preemption to invalidate any state regulations.
In legal terms, when we are talking about the preemption doctrine, this means to the existence to a higher level of law can displace a lower level of the law, in the case, there would be a conflict between the two. So when any federal legislation dictates something that is against state legislation or vice versa, the judicial branch follows the doctrine of preemption to solve the issue. We are talking about the Supremacy Clause that is included in the United States Constitution. You can find it on Article VI; section 2.
