Which of the following is the strongest oxidising agent ?

• A

  ${\mathrm{BrO}}_3^{-}/{\mathrm{Br}}^{2+}, {\mathrm{E}}^0 = +1.50$

• B

  ${\mathrm{Fe}}_{ }^{3+}/{\mathrm{Fe}}^{2+}, {\mathrm{E}}^0 = +0.76$

• C

  ${\mathrm{MnO}}_4^{-}/{\mathrm{Mn}}^{2+}, {\mathrm{E}}^0 = +1.52$

• D

  ${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}/{\mathrm{Cr}}^{3+}, {\mathrm{E}}^0 = +1.33$