The expression relating mole fraction of solute $(x_2)$ and molarity $(M)$ of the solution is (where $\rho$ is the density of solution,$M_1$ and $M_2$ are the molar masses of solvent and solute,respectively)

Question

$\begin{array}{1 1}x_2=\large\frac{MM_1}{M(M_1-M_2)+\rho}\\x_2=\large\frac{MM_1}{M(M_1-M_2)-\rho}\\x_2=\large\frac{M(M_1-M_2)+\rho}{MM_1}\\x_2=\large\frac{M(M_1-M_2)-\rho}{MM_1}\end{array} $