In the reaction,

${\mathrm{I}}_2 + 2{\mathrm{S}}_2{\mathrm{O}}_3^{2-} \stackrel{ }{\to } 2{\mathrm{I}}^{-} + {\mathrm{S}}_4{\mathrm{O}}_6^{2-}$

Equivalent weight of iodine will be equal to

twice of its molecular weight

Its molecular weight

1/4 of its molecular weight

1/2 of its molecular weight