Hund's Rule States That the Most Stable Arrangement of Electrons $m _ { \ell }$

Hund's rule states that the most stable arrangement of electrons (for a ground state electron configuration)

A) has a filled valence shell of electrons.
B) has three electrons per orbital, each with identical spins.
C) has $m _ { \ell }$ values greater than or equal to +1.
D) has the maximum number of unpaired electrons, all with the same spin.
E) has two electrons per orbital, each with opposing spins.