The mutual induction happens in?

Explanation

Option A: AC generator generates electrical power through the principles of electromagnetic induction, but it does not involve mutual induction. In a generator, a rotating coil or magnet generates an alternating current by inducing a voltage in the coil or wire. However, this is a self-induction effect, where the changing magnetic field in the coil induces a voltage in the same coil. Option B: DC generator generates electrical power through the principles of electromagnetic induction, but it does not involve mutual induction. In a generator, a rotating coil or magnet generates an alternating current by inducing a voltage in the coil or wire. However, this is a self-induction effect, where the changing magnetic field in the coil induces a voltage in the same coil. Option C: A battery is a device that converts chemical energy into electrical energy and does not involve induction. Option D: Transformers work on the principle of mutual induction. Mutual Induction is a phenomenon in which changing current in one coil induces an e.m.f. in another coil.