Answer
Please see the work below.
Work Step by Step
We know that
a. An increased mass for the same volume means a higher density for the solution as $d=\frac{m}{V}$.
b. The density will be higher as compared to part "a" as there will be less water for the same mass.
c. The density will be lower than in par "a" as there will be greater volume of water for the same mass of salt.
