Which one is the correct formula for molar mass of solute in the case of boiling point elevation?

Question

Accepted Answer

$\rm{M_{2}=\frac{1000\,K_{b}W_{2}M_{1}}{T_{b}W_{1}}}$

Answer

$\rm{M_{2}=\frac{1000\,K_{b}W_{2}}{T_{b}}}$

Answer

$\rm{M_{2}=\frac{K_{b}W_{1}T_{b}}{1000}}$

Answer

$\rm{M_{2}=\frac{1000\,T_{b}W_{2}}{K_{b}}}$