Final answer:
Eddy currents are produced by moving a conductor in a magnetic field and by changing the magnetic field; they occur in any conductive material and lead to magnetic damping.
Step-by-step explanation:
Eddy currents are induced in conductors when there is relative motion between a magnetic field and the conductor, or when there is a change in the magnetic field itself. So, when considering the options provided, both moving a conductor in a magnetic field and changing the magnetic field can produce eddy currents, not just one or the other exclusively. Eddy currents do not necessarily require the material to be magnetic, and they can be induced in any conductor. The presence of eddy currents often leads to magnetic damping, which is a drag force that opposes the motion of the conductor. This principle is utilized in various applications, such as in braking systems in trains or roller coasters and in metal detectors.