The correct option is C Its ionization isomers cannot be differentiated by silver nitrate solution
(a): Co(NH3)4Br2NO2 can show ionisation and geometrical isomerism. Ionisation isomers are [Co(NH3)4Br2]NO2 and [Co(NH3)4BrNO2]Br
This can also show linkage isomerism as NO2 can either bind with N and O.
(b): Due to the presence of mirror symmetry, it does not show optical isomerism.
(c): [Co(NH3)4Br2]NO2 and [Co(NH3)4BrNO2]Br can be differentiated by AgNO3 solution as the latter will give a yellow ppt of AgBr.
(d): Co is in the +3 oxidation state, here NH3 acts as a strong field ligand and facilitates pairing. Hence, a low spin inner orbital complex will be formed with d2sp3 hybridisation.