Rolf is comparing four solutions. Solution A was placed in the fridge, which is at 4°C. Solution B was placed at room temperature, which is 20°C. Solution C was placed in an incubator at 37°C, and solution D was boiled at 100°C. Rolf then added the same amount of solute into each solution and agitated it at the same speed. The chart indicates his results for the amount of solute dissolved.