Match List - I with List - II. List - I Chromium (III) Complexes...

The crystal field splitting energy $\Delta_0$ depends on the strength of the ligand.

According to the spectrochemical series, the order of ligand strength is $F^- < H_2O < en < CN^-$.

Thus, the order of $\Delta_0$ for the given complexes is $[CrF_6]^{3-} < [Cr(H_2O)_6]^{3+} < [Cr(en)_3]^{3+} < [Cr(CN)_6]^{3-}$.

Matching with the given values:
$[CrF_6]^{3-}$ has the minimum $\Delta_0 = 15,060$ cm$^{-1}$ (B $\rightarrow$ I).
$[Cr(H_2O)_6]^{3+}$ has $\Delta_0 = 17,400$ cm$^{-1}$ (C $\rightarrow$ II).
$[Cr(en)_3]^{3+}$ has $\Delta_0 = 22,300$ cm$^{-1}$ (D $\rightarrow$ III).
$[Cr(CN)_6]^{3-}$ has the maximum $\Delta_0 = 26,600$ cm$^{-1}$ (A $\rightarrow$ IV).

This corresponds to A-IV, B-I, C-II, D-III.

Answer: A-IV, B-I, C-II, D-III