What Is the Freezing Point of an Aqueous Solution of NaCl

Multiple Choice

What is the freezing point of an aqueous solution of NaCl that boils at 102.5°C? (For water, K_f = 1.86°C/m; K_b = 0.52°C/m)

A) 2.5°C
B) -2.5°C
C) -0.70°C
D) 0.70°C
E) -8.9°C