Which pair of liquids shows positive deviation from Raoult's law?

Which of the following pairs will form an ideal solution?

Liquid $A$ and $B$ form an ideal solution. The vapour pressure of pure liquids $A$ and $B$ are $350 \ mm \ Hg$ and $750 \ mm \ Hg$ respectively at the same temperature. If $x_A$ and $x_B$ are the mole fractions of $A$ and $B$ in the solution,and $y_A$ and $y_B$ are the mole fractions of $A$ and $B$ in the vapour phase,then:

Solution $A$ contains acetone dissolved in chloroform and solution $B$ contains acetone dissolved in carbon disulphide. The type of deviations from Raoult's law shown by solutions $A$ and $B$,respectively,are:

Which of the following is not correct?

What is a non-ideal solution and what is meant by positive deviation from Raoult's law?