In CRYSTAL FIELD THEORY (CFT) for an OCTAHEDRAL complex, the five degenerate d-orbitals of the free metal ion split into

1. NCERT §5.6 (Crystal Field Theory): In an octahedral ligand field, the five d orbitals are no longer degenerate. 2. The orbitals pointing DIRECTLY toward the six ligands ($d_{z^2}, d_{x^2-y^2}$) — labelled $e_g$ — are RAISED in energy (more repulsion from ligand lone pairs). 3. The orbitals pointing BETWEEN ligand axes ($d_{xy}, d_{xz}, d_{yz}$) — labelled $t_{2g}$ — are LOWERED in energy. 4. So: $t_{2g}$ (3 orbitals) BELOW $e_g$ (2 orbitals). The splitting energy is denoted $\Delta_o$ (octahedral crystal field splitting). 5. Option B inverts the order. Option C splits too much. Option D contradicts the basic CFT picture. _Source: NCERT Class 12 Chemistry Part 1, Ch 5, §5.6 (Crystal Field Theory — octahedral splitting), p. 10–12._