A solution of 0.438 M means 0.438 mol of $K_2 CrO_4$ is present in 1L of the solution.

Now, Mass of K2CrO4 dissolved per litre of the solution = $0.438 \times 194 = 84.972 g$

Mass of 1L of solution = $1000 \times1.063 = 1063$ g

Amount of water in 1L of solution= 978.028

Assuming $K_2CrO_4$ to be completely dissociated in the solution, we will have;

Amount of total solute species in the solution = 3 $\times$ 0.438 = 1.314 mol.

Finally, Vapour pressure of water above solution = 0.976 $\times$ 23.79 = 23.22 mm Hg

Hence (B) is the correct answer.