Answer: The contract law
Step-by-step explanation:
The free exercise law says that people can practice whatever religion they want and no one should force a religion on someone.
Contracts Clause is in a section in the Constitution whereby the state is prohibited from doing certain things. The aim of the prohibitions is to protect citizens from state governments intrusion.
The preemption doctrine simply means that when there's dispute between two authorities, the law of the authority of law which is lower will be displaced by a higher authority.
Therefore, the correct answer is contract law.