Which one of the following complex ions

$\left[\mathrm{Co}(\mathrm{en})_{3}\right]^{3+}$

$\left[\mathrm{Ni}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Br}\right]^{+}$

$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{2}(\mathrm{en})_{2}\right]^{3+}$

$\left[\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{4}(\mathrm{en})\right]^{3+}$