For $\mathrm{H}{}_2(\mathrm{g})+\mathrm{I}{}_2(\mathrm{g})\rightleftharpoons 2\mathrm{HI}(\mathrm{g})$, $K_c=50$ at a given temperature. Four mixtures are prepared in vessels at this temperature. A mixture with $Q_c=K_c$ is already at equilibrium and shows no net reaction. In which mixtures will the net reaction proceed in the backward direction (towards $\mathrm{H}{}_2$ and $\mathrm{I}{}_2$)?

1. A$[\mathrm{H}{}_2]=0.10$, $[\mathrm{I}{}_2]=0.10$, $[\mathrm{HI}]=1.00$ (all in M)
2. B$[\mathrm{H}{}_2]=0.20$, $[\mathrm{I}{}_2]=0.20$, $[\mathrm{HI}]=1.00$ (all in M)
3. C$[\mathrm{H}{}_2]=0.05$, $[\mathrm{I}{}_2]=0.10$, $[\mathrm{HI}]=0.50$ (all in M)
4. D$[\mathrm{H}{}_2]=0.04$, $[\mathrm{I}{}_2]=0.05$, $[\mathrm{HI}]=0.80$ (all in M)