Solution:Concept- According to Raoult's law, a solvent's partial vapour pressure in a solution (or mixture) is equal to or the same as the pure solvent's vapour pressure times the mole fraction present in the solution.
Raoult's law equation is expressed mathematically as;
Solution = vapour pressure of the solution
Χsolvent = mole fraction of the solvent
P 0 solvent is equal to the pure solvent's vapour pressure.
By Raoult’s law,
But A is a non-volatile solute
So Hence, the correct answer is option 3).