1. Identify geometry and ligand types

Both complexes are octahedral chromium complexes.

• $\left[\mathrm{CrCl}_3(\mathrm{py})_3\right]$ is of type $MA_3B_3$.
• $\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$ is of type $M(AA)_2B_2$, where $AA$ is a bidentate ligand (oxalate).

2. First complex: $\left[\mathrm{CrCl}_3(\mathrm{py})_3\right]$

For an octahedral complex of type $MA_3B_3$, there are two geometrical isomers:

1. fac: the three identical ligands occupy one face of the octahedron.
2. mer: the three identical ligands lie in a meridional plane.

So, for $\left[\mathrm{CrCl}_3(\mathrm{py})_3\right]$:

• geometrical isomers $= 2$
• no optical isomerism for these forms

Hence total stereoisomers $= 2$.

3. Second complex: $\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$

This is an octahedral complex of type $M(AA)_2B_2$.

Such complexes show:

• cis isomer
• trans isomer

Now check optical activity:

(i) trans-$M(AA)_2B_2$

The two identical monodentate ligands ($\mathrm{Cl}^-$) are opposite each other. This form has a plane/center of symmetry and is optically inactive.

So trans gives 1 stereoisomer.

(ii) cis-$M(AA)_2B_2$

The two chloride ligands are adjacent. Because of the arrangement of two bidentate oxalate ligands, the cis form becomes chiral and exists as:

• $\Delta$
• $\Lambda$

So cis gives 2 stereoisomers.

Therefore total stereoisomers for $\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$:

$1 + 2 = 3$

4. Final count

• $\left[\mathrm{CrCl}_3(\mathrm{py})_3\right]$: $2$
• $\left[\mathrm{CrCl}_2(\mathrm{ox})_2\right]^{3-}$: $3$

So the required pair is:

$2 \text{ and } 3$

5. Option check

• A: $3,3$ ❌
• B: $2,3$ ✅
• C: $1,2$ ❌
• D: $2,2$ ❌

Therefore, the correct option is B.