What causes a magnetic field to form around certain metals, such as iron?
a.
the majority of the atoms have been acted upon by gravity.
b.
the majority of the domains are aligned.
c.
the majority of non-metal atoms are aligned.
d.
the majority of the protons are aligned.

Option B. The majority of the domains are aligned.

Magnetic domains is a theory that explains the magnetization in ferromagnetic materials.

Magnetic domains are regions inside a magnetic material in which the magnetic moments of the atoms are parallel, have the same direction. Different magnetic domains have different directions but when the directions of most magnetic domains point in the same direction then the magnetization occurs.

Edit the post so i can see the letters for each answer, and increase the points required so i'd be able to answer it.