The number of species from the following that are involved in $\mathrm{sp}^3 \mathrm{~d}^2$ hybridization is $$ \left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}, \mathrm{SF}_6,\left[\mathrm{CrF}_6\right]^{3-},\left[\mathrm{CoF}_6\right]^{3-},\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-} \text { and }\left[\mathrm{MnCl}_6\right]^{3-} $$