Magnesium Chloride Is Often Used to Melt Ice on Sidewalks $\circ$

Magnesium chloride is often used to melt ice on sidewalks. Considering that the solubility of magnesium chloride (95.21 g/mol) in water is 54.3 g per 100.0 g of water, what is the lowest temperature that you would expect to be able to melt ice with magnesium chloride? Assume ideal behavior. K_f (water) = 1.86 ^$\circ$ C/m

A) (-40 ^$\circ$ C)
B) (-32 ^$\circ$ C)
C) (-11 ^$\circ$ C)
D) (-25 ^$\circ$ C)
E) (-22 ^$\circ$ C)