Which one of the following metal complexes is most stable?

Complex $\left[\mathrm{Co}(\mathrm{en}{)}_3\right]{\mathrm{Cl}}_2$ is most stable complex
among the given complex compounds because
more number of chelate rings are present in this complex as compare to others.

$\left(1\right)\left[\mathrm{Co}\left(\mathrm{en}\right){\left({\mathrm{NH}}_3\right)}_4\right]{\mathrm{Cl}}_2 1$ chelate ring
$\left(2\right)\left[\mathrm{Co}(\mathrm{en}{)}_3\right]{\mathrm{Cl}}_2 3$ chelate ring
$\left(3\right)\left[\mathrm{Co}(\mathrm{en}{)}_2{\left({\mathrm{NH}}_3\right)}_2\right]{\mathrm{Cl}}_2 2$ chelate ring
(4) $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]{\mathrm{Cl}}_2 0$ chelate ring