Examine the Following Half-Reactions and Select the Weakest Reducing Agent

Examine the following half-reactions and select the weakest reducing agent among the substances. Cr(OH) ₃(s) + 3e⁻ ⇄ Cr(s) + 3OH⁻(aq) E° = −1.48 V
SnO₂(s) + 2H₂O(l) + 4e⁻ ⇄ Sn(s) + 4OH⁻(aq) E° = −0.945 V
MnO₂(s) + 4H⁺(aq) + 2e⁻ ⇄ Mn²⁺(aq) + 2H₂O(l) E° = 1.224 V
Hg₂SO₄(s) + 2e⁻ ⇄ 2Hg(l) + SO₄²⁻(aq) E° = 0.613 V

A) Cr( s)
B) Sn( s)
C) Mn ²⁺( aq)
D) Hg( l)
E) OH ⁻( aq)