Strong reducing and oxidizing agents among the following, respectively, are:
\( \mathrm{Ce}^{4+} \) and \( \mathrm{Tb}^{4+} \)
\( \mathrm{Ce}^{4+} \) and \( \mathrm{Eu}^{2+} \)
\( \mathrm{Eu}^{2+} \) and \( \mathrm{Ce}^{4+} \)
\( \mathrm{Ce}^{3+} \) and \( \mathrm{Ce}^{4+} \)