ANS:B - >1

The selectivity of the solvent used in solvent extraction should be greater than 1. Selectivity in solvent extraction refers to the preference of the solvent for one component over another in the mixture being separated. A selectivity value greater than 1 indicates that the solvent has a greater affinity for one component compared to the other. This property is desirable because it helps to achieve efficient separation of the desired component from the mixture. Therefore, the correct answer is > 1.