Which one of the following 0.06 M aqueous solutions has lowest freezing point?

Strategy:\n> Freezing point is a colligative property. Lowest freezing point corresponds to the highest depression in freezing point ($\Delta T_f$), which is achieved by the solution with the highest total concentration of particles ($i \\times M$).\n\nStep 1: Analyze dissociation for each solute\n1. $\ce{Al2(SO4)3}$: $\ce{Al2(SO4)3 \rightarrow 2Al^3+ + 3SO4^2-}$ ($i = 5$)\n2. $\ce{C6H12O6}$: Non-electrolyte ($i = 1$)\n3. $\ce{KI}$: $\ce{KI \rightarrow K+ + I-}$ ($i = 2$)\n4. $\ce{K2SO4}$: $\ce{K2SO4 \rightarrow 2K+ + SO4^2-}$ ($i = 3$)\n\nStep 2: Compare effective concentrations ($i \\times M$)\nGiven $M = 0.06$ for all.\n1. $5 \\times 0.06 = 0.30$\n2. $1 \\times 0.06 = 0.06$\n3. $2 \\times 0.06 = 0.12$\n4. $3 \\times 0.06 = 0.18$\n\nConclusion:\n$\ce{Al2(SO4)3}$ has the highest effective concentration, thus the lowest freezing point.\n\n$\boxed{\\text{Answer: (1) } \ce{Al2(SO4)3}}$