Geometrical isomerism in square planar complexes is given by

• Cis-trans isomerism is a word used in chemistry that refers to the spatial arrangement of atoms inside molecules. 
• It is also referred to as geometric or configurational isomerism. "This side of" and "the other side of" are the meanings of the Latin prefixes "cis" and "trans," respectively.

Hence, the correct option is - Option (C)  ${\mathrm{Ma}}_2{ \mathrm{b}}_2$  type complex