The correct option is B The lattice energy of Barium sulphate is more than its hydration energy
Hydration energy>Lattice energy
BaSO4 is sparingly soluble in water becuase its hydration energy is lesser than the lattice energy and thus ions are not separated from each other. On the contrary in Na2SO4, the hydration energy is more than its lattice energy. Thus ions are separated from each other and pass in solution state.