1. Identify the coordination number and geometry

   The complex is given as $\mathrm{MABXL}$, where $A, B, X,$ and $L$ are all unidentate ligands.

   So, the metal is attached to 4 ligands.

   Since the metal involves $\mathrm{sp}^3$ hybridization, the geometry is tetrahedral.

2. Recall geometrical isomerism in tetrahedral complexes

   For a tetrahedral complex, all four positions are equivalent due to the symmetric 3D arrangement.

   Hence, tetrahedral complexes do not show geometrical isomerism of the cis-trans / fac-mer type.

3. Apply to the given complex

   The complex $\mathrm{MABXL}$ is of the type $\mathrm{Mabcd}$, i.e. four different unidentate ligands around a tetrahedral metal center.

   Such a tetrahedral complex can show optical isomerism in some cases, but it does not show geometrical isomerism.

4. Therefore

   Number of geometrical isomers $= 0$.

5. Option check

   • A: $0$ ✅
   • B: $2$ ❌
   • C: $3$ ❌
   • D: $4$ ❌

Therefore, the correct answer is A.