⇒Coordination_compound

Correct Option is (B)

Formation of [CoF${}_6$]${}^{3-}$

It is an example of sp${}^3$d${}^2$ hybridization. An octahedral complex shows paramagnetic behaviour. It is therefore called outer orbital or high spin or spin free complex.

Orbitals of Co${}^{3+}$ ion

Since F${}^{-}$ is a weak ligand, there is no spin pairing effect and Co${}^{3+}$ possesses 4 unpaired electrons.

Co${}^{3+}$ undergoing sp${}^3$d${}^2$ hybridization

[CoF${}_6$]${}^{3-}$ (Outer orbital or High spin complex)