At the security area of an airport, you walk through a weak AC magnetic field inside a coil of wire. What is the result of a small piece of metal on your person that slightly alters the magnetic field in the coil?Answer

A. Temperature differences are induced in the metal that can be detected by the coil of wire, this in turn changes the AC current in the coils and sets off an alarm.
B. Radiation is induced in the metal that can be detected by the coil of wire, this in turn changes the AC current in the coils and sets off an alarm.
C. Electric currents are induced in the metal that changes the magnetic field, this in turn changes the AC current in the coils and sets off an alarm.