Redox Reactions

Which one of the following options represents the decreasing order of oxidation number of the central atom in:

\(\mathrm{Cr}_2 \mathrm{O}_7^{2-}, \mathrm{Cr} \mathrm{O}_2^{-}, \mathrm{MnO}_4^{-}, \mathrm{BrO}_3^{-}\)