Find the number of reagent(s) which oxidized ${\mathrm{HCO}}_3^{-}$ion solution.

${\mathrm{MnO}}_4^{-}/{\mathrm{H}}^{+},{\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}/{\mathrm{H}}^{+}$, ${\mathrm{Cl}}_2$- water, ${\mathrm{Br}}_2$- water, ${\mathrm{I}}_2$- water

Out of given regent, no regent  is used to oxidized ${\mathrm{HCO}}_3^{-}$ion solution.

${\mathrm{MnO}}_4^{-}/{\mathrm{H}}^{+},{\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}/{\mathrm{H}}^{+}$, ${\mathrm{Cl}}_2$- water, ${\mathrm{Br}}_2$- water, ${\mathrm{I}}_2$- water

hence,  correct answer is 0.