What is the no. of geometric isomers of M[A₂B₂C₂] ?

For MLa2Lb2Lc2, a total of six isomers are possible.

One isomer in which all three pairs of identical ligands are trans
Three distinct isomers in which one pair of identical ligands (La or Lb or Lc) is trans while the other two are cis.
Two enantiomeric chiral isomers in which all three pairs of identical ligands are cis.The number of possible isomers can reach 30 for an octahedral complex with six different ligands (in contrast, only two stereoisomers are possible for a tetrahedral complex with four different ligands).