Of the following $0.10\text{m}$ aqueous solutions, which one will exhibit the largest freezing point depression?

Freezing point depression $\Delta T_f$ is a colligative property given by:
$$\Delta T_f=i\times K_f\times m$$
Since the molality ($m$) is the same for all, $\Delta T_f\propto i$ (van't Hoff factor).$\text{KCl}\to {\text{K}}^{+}+{\text{Cl}}^{-}⟹i=2$${\text{C}}_6{\text{H}}_{12}{\text{O}}_6$ (Glucose) $⟹i=1$ (non-electrolyte)${\text{Al}}_2({\text{SO}}_4{)}_3\to 2{\text{Al}}^{3+}+3{\text{SO}}_4^{2-}⟹i=5$${\text{K}}_2{\text{SO}}_4\to 2{\text{K}}^{+}+{\text{SO}}_4^{2-}⟹i=3$ The largest $i$ value is for ${\text{Al}}_2({\text{SO}}_4{)}_3$, hence it will show the largest freezing point depression.