What Happens When the Low-Voltage Current Flow in the Coil

What happens when the low-voltage current flow in the coil primary winding is interrupted by the switching device?

A) The magnetic field around the primary winding collapses
B) The movement of the magnetic field across the winding induces a high voltage in the secondary winding
C) both "The magnetic field around the primary winding collapses" and "The movement of the magnetic field across the winding induces a high voltage in the secondary winding"
D) neither "The magnetic field around the primary winding collapses" nor "The movement of the magnetic field across the winding induces a high voltage in the secondary winding"