The correct option is B chloride > sulphate > phosphate
A compound is soluble in water if its lattice energy is less than hydration energy. Lattice energy depends on the product of the charges of the cation and the anion and inversely proportional to the internuclear distance between them.
Here, Charge on the anion increases as Cl−<SO2−4<PO3−4 and the size increases in the same order Cl−<SO2−4<PO3−4. As a result, the net lattice energy increases as follows: NaCl<Na2SO4<Na3PO4 as charge is dominating factor here.
Hence, the order of solubility is NaCl>Na2SO4>Na3PO4.