We know the following standard reduction potentials for element M at 25°C:
MO₄⁻(aq) + 8H⁺(aq) + 5e⁻ → M²⁺(aq) + 4H₂O(l), ε₁° = 2.126V
MO₂(s) + 4H⁺(aq) + 2e⁻ → M²⁺(aq) + 2H₂O(l), ε₂° = -1.450V
A) MO₄⁻ + 4H⁺ + 2e⁻ → MO₂ + 2H₂O, ε = -3.576V
B) MO₂ + 4H⁺ + 5e⁻ → MO₄⁻ + 2H₂O, ε = 3.576V
C) MO₄⁻ + MO₂ → M + 2H₂O, ε = 3.576V
D) M + 2H₂O → MO₄⁻ + MO₂, ε = -3.576V