c) According to Hund's Rule, electrons will occupy each orbital within a sub-shell singly with parallel spins before any orbital is doubly occupied. This arrangement minimizes electron-electron re

c) According to Hund's Rule, electrons will occupy each orbital within a sub-shell singly with parallel spins before any orbital is doubly occupied. This arrangement minimizes electron-electron repulsion and maximizes exchange energy, leading to a more stable configuration. For a $3p$ sub-shell, this means that a half-filled configuration ($3p^3$, with one electron in each of the three $p$ orbitals, all with parallel spins) or a fully-filled configuration ($3p^6$) is particularly stable due to this principle and increased symmetry.