Coordination Compounds

\(\text { Observe the following complex ions }\)

$$ \begin{array}{cccc} \hline\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-} & {\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}} & {\left[\mathrm{CoF}_6\right]^{3-}} & {\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}} \\ \hline A & B & C & D \\ \hline \end{array} $$

Identify the option in which the unpaired electrons in the complex ions are in correct increasing order