Which of the following is a non-electrolyte?

The relative lowering of vapour pressure for $0.1 \ M$ aqueous solutions of $NaCl$,$CuSO_4$,and $K_2SO_4$ is in the ratio of...

The freezing point of a solution prepared by adding $8.1 \ g$ of $HBr$ ($90\%$ ionized) to $100 \ g$ of water is $...... \ ^\circ C$. (Given $K_f$ for water $= 1.86 \ K \ kg \ mol^{-1}$)

The elevation in boiling point of a solution of $10 \ g$ of a binary electrolyte (of molecular mass $100$) in $100 \ g$ of water is $\Delta T_b$. Then,the value of $K_b$ for water is

The freezing point of an aqueous solution which contains $5\%$ by mass urea,$1.0\%$ by mass $KCl$,and $10\%$ by mass glucose is ........ $K$. $\left( K_f(H_2O) = 1.86 \ K \ kg \ mol^{-1} \right)$

Among the given solutions,which one has the highest boiling point under similar conditions?