Which of the Following Accurately Represents the Oxidation of the Co⁺²

Which of the following accurately represents the oxidation of the Co⁺² ion?

A) Co⁺² + 2 e^- $\rightarrow$ Co
B) Co⁺² $\rightarrow$ Co⁺³ + e^-
C) Co $\rightarrow$ Co⁺² + 2 e^-
D) Co⁺³ + e^- $\rightarrow$ Co⁺²