Which statement(s) is/are correct for the transition metal complex $[{Co(en)}_2{Cl}_2{]}^{+}$, where $en$ represents the bidentate ligand ethylenediamine?

1. The oxidation number of $Co$ is +3.
2. It can exist as both optical and $cis$-$trans$ isomers.
3. The coordination number of $Co$ is 4.