Which of the Following Shows the Correct Expression for the Ionization

Which of the following shows the correct expression for the ionization energy indicated?

A) $\mathrm{IE}_{3}: \mathrm{Al}(g) \rightarrow \mathrm{Al}^{3+}(g) +3 \mathrm{e}^{-}$
B) $\mathrm{IE}_{1}: \mathrm{Cl}(g) \rightarrow \mathrm{Cl}^{+}(g) +\mathrm{e}^{-}$
C) $\mathrm{IE}_{2}: \mathrm{Mg}(g) \rightarrow \mathrm{Mg}^{2+}(g) +2 \mathrm{e}^{-}$
D) $\mathrm{IE}_{1}: \mathrm{Na}(s) \rightarrow \mathrm{Na}^{+}(g) +\mathrm{e}^{-}$
E) $\mathrm{IE}_{3}: \mathrm{O}_{2}(g) \rightarrow \mathrm{O}_{2}^{+}(g) +\mathrm{e}^{-}$