Magnesium Chloride Is Often Used to Melt Ice on Sidewalks

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°C/m

A) -40°C
B) -32°C
C) -11°C
D) -25°C
E) -22°C