Out of the following pairs (of complexes), in which option, first complex is more stable than second complex :

Options

A. `[Co(NO_(2))_(6)]^(4-)" and "[Co(NO_(2))_(6)]^(3-)`
B. `[Co(H_(2)O)_(6)]^(2+)" and "[Co(NH_(3))_(6)]^(2+)`
C. `[Co(trien)]^(2+)" and "[Co(en)_(2)]^(2+)`
D. `[Mn(NH_(3))_(6)]^(2+)" and "[Ni(NH_(3))_(6)]^(2+)`

Answer

C

Explanation

`[Ci(trien)]^(2+)` has better chelation.