Which of the following equations correctly represents the molar mass of a solute by knowing the boiling point elevation?

• A
  $M_2 = \frac{1000 \times K_b \times W_2}{\Delta T_b \times W_1}$
• B
  $M_2 = \frac{1000 \times K_b \times W_1}{\Delta T_b \times W_2}$
• C
  $M_2 = \frac{1000 \times \Delta T_b \times W_1}{K_b \times W_2}$
• D
  $M_2 = \frac{1000 \times K_b \times W_2}{\Delta T_b \times W_1}$