Christopher is given identical volumes of two different solutions. He hypothesizes that solution A has a higher water concentration than solution B. Which experimental design would best allow him to test his hypothesis?

A.) Place five drops of vegetable oil in solution A and five drops of mineral oil in solution B. Make note if the oils sink or float.

B.) Mix solution A and solution B together in a large graduated cylinder. Measure the mass and the total volume of the combined solutions. Make note of the density of the combined solutions.
C.)Use litmus paper to test the acidity and basicity of solution A and solution B. Make note if the paper turns red or blue.

D.)Place solution A in a membrane that is permeable to water. Then, place the membrane full of solution A into a beaker full of solution B. Make note of the direction in which water flows.