Which of the following has an optical isomer?
(en=ethylenediamine) ?

Options

A. `[Zn(en)_(2)]^(2+)`
B. `[Zn(en)(NH_(3))_(2)]^(2+)`
C. `[Co(en)_(3)]^(3+)`
D. `[Co(H_(2)O)_(4)en]^(3+)`

Answer

3

Explanation

(3) has unsymmetrical octahedral structure