Which one of the following has largest number of isomers ? (R = alkyl group , en = ethylenediamine)

Options

A. a.`[Cr(en)_(2)Cl_(2)]^(o+)`
B. b.`[Cr(NH_(3))_(5)Cl]^(2+)`
C. c.`[Ru(NH_(3))_(4)Cl_(2)]^(o+)`
D. d.`[Ir(PR_(3))_(2)(CO)
_(2)]^(2+)`

Answer

A

Explanation

`Co(en)_(2)CI_(2)]^(o+)` shows geometrical as well as optical isomerism .