Consider the Following Standard Reduction Potentials in Acid Solution The Weakest Reducing Agent Listed Above Is
A) Cr³⁺

Consider the following standard reduction potentials in acid solution: $\begin{array}{ll}\mathrm{Cr}^{3+}+3 \mathrm{e}^{-} \rightarrow \mathrm{Cr} & \mathrm{E}^{\circ}=-0.74 \mathrm{~V} \\\mathrm{Co}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Co} & \mathrm{E}^{\circ}=-0.28 \mathrm{~V} \\\mathrm{MnO}_{4^{-}}+8 \mathrm{H}^{+}+5 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{2+}+4 \mathrm{H}_{2} \mathrm{O} & \mathrm{E}^{\circ}=+1.51 \mathrm{~V}\end{array}$ The weakest reducing agent listed above is

A) Cr³⁺.
B) Cr.
C) Mn²⁺.
D) Co.
E) MnO₄^-.