Answer:
d. the electrons in some metals pair up to create a magnetic field.
Step-by-step explanation:
Magnetism is the property of attraction and repulsion of certain metals and magnets, which have a positive and a negative pole, characterized by “dipole forces”. When magnetism occurs the electrons in some metals come together to create a magnetic field. The Magnetic Field, in turn, is the concentration of magnetism that is created around a magnetic charge in a given space.
It is the electrons of metals that create the magnetic field, just as it is the electric charge and mass that respectively create the electric and gravitational fields.