Lenz's law is a fundamental law in physics that states that the direction of an induced current in a conductor will be such that it opposes the change that produced it. In simpler terms, Lenz's law is a law of conservation of energy that describes the direction of induced current in relation to a changing magnetic field. When a magnetic field changes, an electric current is induced in a conductor, and the direction of the induced current is such that it opposes the change in the magnetic field. Therefore, the correct answer is Energy.