Calculate the Enthalpy of Solution for the Dissolution of Sodium

Calculate the enthalpy of solution for the dissolution of sodium chloride, NaCl, molar mass = 58.443 g mol^-1. When 6.93 g of NaCl is dissolved in a coffee cup calorimeter containing 100.0 mL of water the temperature dropped from 23.5 °C to 22.4 °C. The specific heat of water is 4.184 J g^-1 °C^-1, and assume the density of the solution is 1.00 g mL^-1.

A) -2.8 kJ mol^-1
B) 3.9 kJ mol^-1
C) -6.4 kJ mol^-1
D) 4.1 kJ mol^-1
E) 6.3 kJ mol^-1