Calculate the Freezing Point of a 2 $\degree$ CK_f (Water) = -1

Calculate the freezing point of a 2.0 m solution of NaCl in water? Remember that NaCl is an electrolyte.The normal freezing point of pure water is 0.00 $\degree$ C.K_f (water) = -1.86 $\degree$ C/m

A) -2.08 $\degree$ C
B) -3.72 $\degree$ C
C) -7.44 $\degree$ C
D) 7.44 $\degree$ C
E) 3.74 $\degree$ C