b
\([Fe(CN)_6]^{3-}\) has magnetic moment of a single unpaired electron whereas \([FeF_6]^{3-}\) has a magnetic moment of five unpaired electrons. \([CoF_6]^{3-}\) is paramagnetic with four unpaired electrons while \([Co(C_2O_4)_3]^3\) is diamagnetic. This anomaly is explained by valence bond theory in terms of formation of inner and outer orbital coordination entities. \([Co(C_2O_4)_3]^{3-}\) is an inner orbital complexes having \(d^2sp^3\) hybridization .