What is the purpose of studying the hysteresis curve of a ferromagnetic material?
To determine the relationship between magnetic flux density and magnetizing force.
To determine the magnetic properties of the material, such as retentivity, residual magnetism, coercive force, permeability, and reluctance.

a) Only item I is correct.
b) Only item II is correct.
c) Both items are correct.
d) None of the items is correct.