Final answer:
Quasi-contracts are contracts that are not created by mutual agreement but are instead imposed by the court to avoid unjust enrichment.
Step-by-step explanation:
The correct answer is quasi-contracts.
Quasi-contracts are contracts that are not created by mutual agreement, but are instead imposed by the court to avoid unjust enrichment. They are based on the principle of fairness and are used when someone has received a benefit or enrichment, usually in the form of goods or services, and it would be unfair for them to keep that benefit without compensating the provider.
For example, if a person accidentally receives a package meant for someone else and refuses to return it, a court may impose a quasi-contract to require them to compensate the rightful owner of the package.