Co-ordination complexes can show stereoisomerism square planar complexes of `Ma_(2)b_(2)` type can show geometrical isomerism but not optical & octahedral complexes of `Ma_(2)b_(2)C_(2), Ma_(3)b_(3) Mabcdef` etc show stereoisomerism, for e.g. `Mabcdef` have 15 geometrical isomers & all are optically active so it has 15 pairs of enantiomers thus in totaly it has 30 stereoisomers. (a,b,c,d etc. are monodentate lignads while `AB` is bidenatate ligand)
Which of the following can show geometrical as well as optical isomerism?