Which one of the following represents all isoelectronic species ?
$\mathrm{Na}^{+}, \mathrm{Cl}^{-}, \mathrm{O}^{-}, \mathrm{NO}^{+}$
$\mathrm{N}_2 \mathrm{O}, \mathrm{N}_2 \mathrm{O}_4, \mathrm{NO}^{+}, \mathrm{NO}$
$\mathrm{Na}^{+}, \mathrm{Mg}^{2+}, \mathrm{O}^{-}, \mathrm{F}^{-}$
$\mathrm{Ca}^{2+}, \mathrm{Ar}, \mathrm{K}^{+}, \mathrm{Cl}^{-}$
