Choice B is a convoluted way of saying that the dissociation reaction is exothermic. If you release more energy when forming the product than you add to break the reactant, then the overall reaction releases energy and is thus exothermic. For an exothermic process, adding heat will push it to the reactant side. This would mean that ignoring the entropy factor (which is actually pretty significant and is being trivialized here), we would predict salts that dissociate exothermically will become less soluble as the temperature of the solution is raised. That is what it shows on the graph for cesium sulfate (Ce2(SO4)2).