One mole each of the following solutes are taken in 1000g of water

Question

 

$\begin{array}{1 1}(A)\;KCl\\(B)\;K_2SO_4\\(C)\;Na_3PO_4\\(D)\;glucose\end{array}$

Assuming 100% ionisation of the electrolyte,relative decrease in vapour pressure will be in order

$\begin{array}{1 1}(a)\;A > B > C > D\\(b)\;A > C > B > D\\(c)\;A > B > D > A\\(d)\;C > B > A > D\end{array}$