Which oxidation states does Cobalt occupy?

Cobalt can indeed occupy the oxidation states of Co(2+) and Co(3+). These are the most common oxidation states found in various cobalt compounds, particularly in coordination chemistry and transition metal chemistry.

In its +2 oxidation state, cobalt often forms compounds such as CoCl2 and is known for being stable and relatively common in nature. The +3 oxidation state can be seen in compounds like CoCl3, which are often less stable than their +2 counterparts but still important in certain chemical reactions, particularly in catalysis and redox processes.

The other oxidation states mentioned in the other choices, such as +1, +4, and +5, are either very rare or not typically observed for cobalt in its typical chemical behavior. Therefore, the most relevant and commonly recognized oxidation states for cobalt are Co(2+) and Co(3+).