A scrapyard uses a big electromagnet to move around large metal objects such as cars and appliances. If the operator needed to drop a car to a new space, what would he need to do for this to happen?
A) The magnetic field cannot be turned off.
B) The magnetic field can be turned off by switching off the current.
C) The magnetic field can be reversed by switching the poles of the core.
D) The magnetic field can be decreased by placing it in proximity to an opposite pole.