Study this chemical reaction: Cr + I₂ = CrI₂. Then, write balanced half-reactions describing the oxidation and reduction that happen in this reaction.

a. Oxidation: Cr → Cr³+ + 3e⁻; Reduction: I₂ + 2e⁻ → 2I⁻
b. Oxidation: Cr → Cr³+ + 2e⁻; Reduction: I₂ + 2e⁻ → 2I⁻
c. Oxidation: Cr → CrI₃ + 2e⁻; Reduction: I₂ + 2e⁻ → 2I⁻
d. Oxidation: Cr + I₂ → CrI₂; Reduction: I₂ + 2e⁻ → 2I⁻