Identify the diamagnetic octahedral complex ions from below ;

A. $\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-}$

B. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$

C. $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$

D. $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_3 \mathrm{~F}_3\right]$

Choose the correct answer from the options given below: