The CFSE for octahedral is 18,000 cm${}^{-1}$ . The CFSE for tetrahedral will be ${\left[CoC{l}_{4}\right]}^{2-}$

1. 6000 cm${}^{-1}$

2. 16,000 cm${}^{-1}$

3. 18,000 cm${}^{-1}$

4. 8,000 cm${}^{-1}$

Hint:  $$\Delta_{t} =\frac{4}{9}\Delta_{o}$$

The relation between $$\Delta_{t}$$ and $$\Delta_{o}$$ is $$\Delta_{t} =\frac{4}{9}\Delta_{o}$$

Where,${∆}_{0}$ CFSE for octahedral complex, ${∆}_{t}$ = CFSE for tetrahedral complex

According to question,

Hence , correct choice is option fourth