$0.0200$ mol of $\mathrm{CoCl}{}_3\cdot 5\mathrm{NH}{}_3$ (Co coordination number 6) gives $0.0400$ mol of $\mathrm{AgCl}$ with excess $\mathrm{AgNO}{}_3$. The compound is dissolved to make a $0.0200$ molal aqueous solution and dissociates completely. Taking $K_f=1.86\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$, the depression of freezing point in K is approximately

1. A0.149
2. B0.074
3. C0.186
4. D0.112