The correct statement on the isomerism associated with the following complex ions, <br> (a) $[Ni(H_2O)_5NH_3]^{2+},$<br>(b)$[ Ni(H_2O)_4 (NH_3)_2]^{2+} $ and <br> (c)$[Ni(H_2O)_3 (NH_3)_3]^{2+} $ is :

Question

( A ) (a) and (b) show only geometrical isomerism
( B ) (b) and (c) show only geometrical isomerism
( C ) (b) and (c) show geometrical and optical isomerism
( D ) (a) and (b) show geometrical and optical isomerism