ANS:A - boiling point

Boiling point elevation for a strong and concentrated solution, according to Duhring's rule, states that at the same pressure, the boiling point of a solution is a linear function of the boiling point of pure water. Duhring's rule is a colligative property, meaning it depends only on the number of solute particles in the solution, not on their identity. It predicts that the boiling point of a solution will be higher than that of the pure solvent due to the presence of solute particles, which disrupt the formation of vapor molecules and thus require a higher temperature to achieve boiling. Therefore, according to Duhring's rule, the boiling point elevation is directly proportional to the boiling point of the pure solvent, typically water.