If the complex ${\text{MA}}_{\text{2}}{\text{B}}_{\text{2}}\text{is}{\text{\hspace{0.17em}sp}}^3$ hybridised then the shape of this complex is tetrahedral this structure is optically inactive due to the presence of plane of symmetry



Optical isomers = 0 (b) If the complex ${\text{MA}}_{\text{2}}{\text{B}}_{\text{2}}\text{is}{\text{dsp}}^2$ hybridised then the shape of this complex is square planar.



Both isomers are optically inactive due to the presence of plane of symmetry. Optical isomers $=0$