Which of the following accurately describes the methodology used in this experiment?

A. Beaker A is used as an experiment to determine how acid affects limestone. Beaker B is used as a second experiment to determine how acid of a higher concentration affects limestone compared to acid of a lower concentration. Beaker C is used as a control to ensure that the limestone does not simply lose volume over time. Beaker D is used as a control to ensure that the limestone does not dissolve in plain water with a neutral pH.

B. Beaker A is used as a control to ensure that the limestone does not simply lose volume over time. Beaker B is used as a control to ensure that the limestone does not dissolve in plain water with a neutral pH. Beaker C is used as an experiment to determine how acid affects limestone. Beaker D is used as a second experiment to determine how acid of a higher concentration affects limestone compared to acid of a lower concentration.

C. Beaker A is used as a control to ensure that the limestone does not simply lose volume over time. Beaker B is used as a control to ensure that the limestone does not dissolve in plain water with a neutral pH. Beaker C is used as an experiment to determine how acid affects limestone. Beaker D is used as a duplicate to ensure that adding acid to the limestone will yield the same results each time.

D. Beaker A is used as an experiment to see the effects of air on limestone. Beaker B is used as an experiment to determine the effects of plain water with a neutral pH on limestone. Beaker C is used as an experiment to determine how acid affects limestone. Beaker D is used as a second experiment to determine how acid of a higher concentration affects limestone compared to acid of a lower concentration. There are no controls in this experiment because a controlled experiment was not practical for this situation.