Amongst $\mathrm{FeCl}_3 .3 \mathrm{H}_2 \mathrm{O}, \mathrm{K}_3\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ and $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3$, the spin-only magnetic moment value of the inner-orbital complex that absorbs light at shortest wavelength is $\_\_\_\_$ B.M.
[nearest integer] $\_\_\_\_$
