Quasi-contracts are based on the doctrine of:

Correct option is A

A quasi-contract is an obligation imposed by law to prevent unjust enrichment, ensuring that no one benefits unfairly at another’s expense. It is not a contract in the traditional sense but is imposed by law in cases where one party benefits unfairly at another’s expense.

Additional Knowledge:
· Unjust enrichment: A principle where one party should not unfairly benefit at another’s cost.
· Just enrichment: Not a recognized legal concept.
· Misrepresentation: A false statement affecting contract validity, unrelated to quasi-contracts.