A solution containing $8.6gL^{-1}$ of urea (molar mass $60gmol^{-1}$) is isotonic with a 5% solution of unknown solute.The molar mass of the solute will be

Question

$\begin{array}{1 1}348.9gmol^{-1}\\174.5gmol^{-1}\\87.3gmol^{-1}\\34.89gmol^{-1}\end{array} $