The correct option is B −0.6Δ0
The complex given here is [Cu(NH3)6]2+.
So it is an octahedral complex.
Here, Cu is +2 oxidation state.
So its electronic configuration is [Ar]3d9
According to the crystal field spliting theory, the electronic configuration in d-orbital will be t62ge3g
So, crystal field stabilization energy will be
=(−0.4×6+0.6×3)Δo=(−2.4+1.8)Δo=−0.6Δo