The question requires us to complete the sentence with the appropriate definition, choosing among the options given (molar mass, solubility, solvent property and bond quality).
The solubility of a substance is defined as the maximum amount of this substance that can be dissolved in a determined amount of a solvent, at a given temperature.
Analyzing the sentence given, we can see that it fits the definition above: the amount of sodium nitrate (the solute) that will dissolve in a given amount of a solvent ( 110 g of water) at a given temperature (2000 °C). Thus, we can say that the sentence should be completed with the word "solubility" and the best option to answer this question is letter B.