Which characteristic is least likely to be used for predicting percent dissociation of a solid in a liquid?

This question should have choices. These are the choices: A.) chemical properties of solute the B.)  type and polarity of the solvent C.) the temperature D.) concentration of solute 
A and B are related and is a huge factor in determining how well substances dissolve. C is again another key factor. Since the more we increase the temperature, for most substances, dissolution also increases. D would have to be the answer. 

Mgo2 is the oxidation state of manganese oxide