Answer
Please see the work below.
Work Step by Step
We know that $HC_2H_3O_2$ is a more strong acid than $H_2S$. On the other hand, $HS^{-}$ is a stronger base than $C_2H_3O_2^{-}$ ion. To achieve the equilibrium, we need the weaker acid and weaker base, hence the reactants are favored.
