\((b)\) Low spin complex
\((c)\) Show geometrical isomerisms geometrical isomer \((1\) cis \(+ 4\) trans)
\((d)\, Ma_3d_3\) type complex show fac and mer form and this complex is \(Ma_2b_2c_2\). type, so does not show fac and mer form
($R $ = alkyl group; $en$ = ethylenediamine)