Concept:A dynamo is a device that converts mechanical energy into electrical energy.
Explanation:A dynamo works on the principle of electromagnetic induction.
Inside a dynamo, a coil is made to rotate within a magnetic field.
This rotation changes the magnetic flux linked with the coil.
As a result, an electric current is induced in the coil.
Thus, the mechanical energy of rotation is transformed into electrical energy.
An electric motor does the reverse, a transformer only changes voltage, and an induction coil produces high voltage pulses.
Answer:A. a dynamo