The number of possible optical isomers for the complexes MA₂B₂ with sp³ and dsp² hydridized metal atom. respectively, is :
Note : A and B are unidentate netural and unidentate monoanionic ligands, respectively.

Among the statements(a)-(d) the incorrect ones are :
(a) Octahedral CO(III) complexes with strong fields ligands have very high magnetic moments.
(b) When $$\Delta $$₀ < P, the d-electron configuration of Co(III) in an octahedral complex is $$t_{eg}^4e_g^2$$
(c) Wavelength of light absorbed by [Co(en)₃]³⁺ is lower than that of [CoF₆]^3-
(d) If the $$\Delta $$₀ for an octahedral complex of CO(III) is 18,000 cm^-1, the $$\Delta $$_t for its tetrahedral complex with the same ligand be 16,000 cm^-1

The theory that can completely/properly explain the nature of bonding in [Ni(Co)₄] is :

The IUPAC name of complex [Pt(NH₃)₂Cl(NH₂CH₃)]Cl is: