Which is the oxidizing agent in the following reaction?

\[{\text{5S}}{{\text{O}}_2}{\text{(g)}} + {\text{2IO}}_3^ - {\text{(aq)}} + {\text{4}}{{\text{H}}_2}{\text{O(l)}} \to {\text{5SO}}_4^{2 - }{\text{(aq)}} + {{\text{I}}_2}{\text{(aq)}} + {\text{8}}{{\text{H}}^ + }{\text{(aq)}}\]

A.     \({\text{S}}{{\text{O}}_{\text{2}}}\)

B.     \({\text{IO}}_{\text{3}}^ - \)

C.     \({{\text{H}}_{\text{2}}}{\text{O}}\)

D.     \({\text{SO}}_{\text{4}}^{2 - }\)

B