The correct option is (b) the solution is 100 times more basic.
Work Step by Step
Since pH level is measured in logarithmic scale, each of the pH value below 7 is ten times more acidic than the next higher value. For example, the pH value 3 is ten times more acidic than pH 4. So, when the pH value changes from 5 to 6, the solution becomes 10 times more basic. Further, when the solution changes from pH 6 to 7 it becomes 10 times more basic again. So overall solution becomes 100 times more basic than the original solution when pH changes from 5 to 7.