Pick out the correct statement with respect to ${\left[\mathrm{Mn}\right(\mathrm{CN}{)}_6]}^{3-}$

$$\begin{gathered} {\left[\mathrm{Mn}(\mathrm{CN}{)}_6\right]}^{3-} \\ \text{ Let oxidation state of }\mathrm{Mn}\text{ be }\mathrm{x}\text{ . } \\ \begin{array}{l}\mathrm{x}+6\times (-1)=-3\\ \mathrm{x}=+3\end{array} \\ \text{ Electronic configuration of }\mathrm{Mn}:\left[\mathrm{Ar}\right]4{\mathrm{s}}^{2}3{\mathrm{d}}^5 \\ \text{ Electronic configuration of }{\mathrm{Mn}}^{3+}:\left[\mathrm{Ar}\right]3{\mathrm{d}}^4 \\ {\mathrm{CN}}^{-}\text{is a strong field ligand thus, it causes pairing of electrons in }3\mathrm{d}\text{ -orbital. } \end{gathered}$$

Thus, ${\left[\mathrm{Mn}(\mathrm{CN}{)}_6\right]}^{3-}\text{ has }{\mathrm{d}}^2{\mathrm{sp}}^3$ hybridisation and has octahedral geometry.