A solution containing 10 g per dm 3 of urea (molecular mass = $60g mol^{-1}$) is isotonic with a 5% solution of a nonvolatile solute. The molecular mass of this nonvolatile solution is:

Question

( A ) $250g mol^{-1}$
( B ) $300g mol^{-1}$
( C ) $350g mol^{-1}$
( D ) $200g mol^{-1}$