c
The octahedral complex with \(C F S E=-0.8 \Delta_{o}\) surrounded by weak field
ligands can have one or more unpaired electrons.
The spin only magnetic moment is given by the formula \(\mu_{e f f}=\) \(\sqrt{n(n+2)} B \cdot M\)
For two unpaired electrons, the expression becomes \(\mu_{e f f}=\sqrt{2(2+2)} B \cdot M .=\) \(\sqrt{8} B \cdot M\)
For three unpaired electrons, the expression becomes \(\mu_{e f f}=\) \(\sqrt{3(3+2)} B \cdot M \cdot=\sqrt{15} B \cdot M\)
Thus, both options \(A\) and \(B\) are correct.