Using the data given below find out the strongest reducing agent.

$\begin{array}{l}{E}_{{\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}/{\mathrm{Cr}}^{3+}}^{⊝}=1.33\mathrm{V}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>;<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>E_{{\mathrm{Cl}}_2/{\mathrm{Cl}}^{-}}^{\ominus }=1.36\mathrm{V}\\ E_{\mathrm{Mn}{0}_4^{-}/{\mathrm{Mn}}^{2+}}^{⊝}=1.51\mathrm{V}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace><mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>;\hspace{0.17em}{E}_{{\mathrm{Cr}}^{3+}/\mathrm{Cr}}^{\ominus }=-0.74\mathrm{V}\end{array}$

1.  Cl^-

2.  Cr

3.  Cr³⁺

4.  Mn²⁺