926 G of an Unknown Solid Is Dissolved in a Coffee

9.26 g of an unknown solid is dissolved in a coffee cup calorimeter that contains 62.0 mL of water. The measured temperature increased from 23.4 °C to 24.7 °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. Calculate the molecular weight of the unknown solid if the Δ_rH was determined to be -2.51 kJ mol^-1 via another experiment.

A) 69 g mol^-1
B) 48 g mol^-1
C) 76 g mol^-1
D) 184 g mol^-1
E) 93 g mol^-1