Moses v. Macferlan (1555-1774) is a case relating to

Solution (By Examveda Team)

Moses v. Macferlan (1555-1774) is a landmark case in English contract law, not specifically Indian Contract Act.

Option A: Theory of unjust enrichment
The theory of unjust enrichment dictates that a person should not be unjustly enriched at another's expense. This means if someone receives a benefit without a valid legal reason, they are required to return it. While Moses v. Macferlan is considered foundational to the development of this principle in English law, it's not solely about unjust enrichment. It's broader than just this theory.

Option B: The right of lien
A lien is a right to retain possession of property belonging to another person until a debt or obligation owed by that person is discharged. Moses v. Macferlan does not primarily deal with the right of lien, though the principles involved might be tangentially related to broader concepts of property rights and obligations.

Option C: Test of agency
Agency refers to a relationship where one person (the agent) acts on behalf of another (the principal). This case is not primarily concerned with establishing tests for agency relationships.

Option D: Doctrine of frustration
The doctrine of frustration in contract law arises when an unforeseen event makes performance of a contract impossible or radically different from what was intended. This doctrine wasn't well-defined in 1760 when Moses v. Macferlan was decided. The case dealt with more fundamental principles of restitution and unjust enrichment, paving the way for later developments in contract law, including perhaps influences on the later formulation of the doctrine of frustration, but wasn’t directly about it.

Correct Answer: Option A (with a caveat)
While Moses v. Macferlan is not *exclusively* about unjust enrichment, it's considered a pivotal case in its development. The case established the principle that money received under a mistake of fact or without consideration must be returned. This concept is central to the theory of unjust enrichment. Therefore, although not solely focused on this theory, it is most accurately associated with it among the given options.