Which physical phenomenon is chiefly responsible for reducing the amplitude of a rapidly varying magnetic field inside a thick copper enclosure surrounding sensitive electronic circuits?
(a) Charge displacement due to dielectric polarization in the copper
(b) Eddy currents induced in the copper oppose the changing magnetic flux
(c) Skin effect confines the alternating magnetic field to the surface of the copper
(d) Resonant absorption of energy at the enclosure's natural frequency