Which of the following formulas correctly gives the value of the ebullioscopic constant $(K_{b})$?

• A
  $\frac{W_{1} \times 1000}{\Delta T_{b} \times W_{2} \times M_{2}}$
• B
  $\frac{W_{2} \times 1000}{\Delta T_{b} \times W_{1} \times M_{2}}$
• C
  $\frac{M_{2} \times \Delta T_{b} \times W_{2}}{W_{1}}$
• D
  $\frac{\Delta T_{b} \times M_{2} \times W_{1}}{W_{2}}$