The number of ions from the following that are expected to behave as oxidizing agent is:\( \mathrm{Sn}^{4+}, \mathrm{Sn}^{2+}, \mathrm{Pb}^{2+}, \mathrm{Tl}^{3+}, \mathrm{Pb}^{4+}, \mathrm{Tl}^{+} \)
\( 1 \)
\( 3 \)
\( 2 \)
\( 4 \)