Which of the following statements is correct regarding the chirality (optical isomerism) of the cis and trans isomers of the type M(aa)2b2 (M stands for a metal, a and b are achiral ligands and aa is a bidentate ligand) ?
List – I
List – II
(a) [Co(NH3)6] [Cr(CN)6]
(i) Linkage isomerism
(b) [Co(NH3)3 (NO2)3]
(ii) Solvate isomerism
(c) [Cr(H2O)6]Cl3
(iii) Coordination isomerism
(d) cis-[CrCl2(ox)2]3-
(iv) Optical isomerism
Identify the optically active compounds from the following (a) [Co(en)3]3+ (b) trans−[Co(en)2Cl2]+ (c) cis−[Co(en)2Cl2]+ (d) [Cr(NH3)5Cl]