Which type of materials are relatively easy to magnetize?

The correct response is based on the inherent properties of ferromagnetic materials. These materials have regions known as magnetic domains, where groups of atoms point in the same direction, creating a net magnetic moment. When an external magnetic field is applied, these domains realign, enhancing the material's overall magnetization.

Ferromagnetic substances, such as iron, cobalt, and nickel, can retain their magnetization even after the external magnetic field is removed, which makes them particularly useful in applications like permanent magnets. The strong interaction between the atomic magnetic moments in ferromagnetic materials facilitates easy magnetization compared to other types of magnetic materials.

The other categories of materials, such as diamagnetic and paramagnetic, do not have the same capability for easy magnetization. Diamagnetic materials are repelled by magnetic fields and do not retain magnetization. Paramagnetic materials can be magnetized in the presence of a magnetic field but do not have the strong interaction needed to retain that magnetization, making them less effective than ferromagnetic materials. Non-magnetic materials lack any magnetic properties and, therefore, cannot be magnetized.