Beetroot cells contain a family of dark red pigments called betalains. The selectively permeable nature of the beetroot cells keeps the internal environment of the cell separate from the external environment of the cell. Researchers are interested in determining whether the selective permeability of beetroot cells is due to the cell membrane or if it is due to the cell wall.

Exposure to cellulase is known to damage the structure of the cell wall. An experiment is set up in which beetroot cells are placed in an aqueous solution with cellulase and in one without cellulase.

Which of the following results best refutes the alternative hypothesis that selective permeability is a consequence of the cell wall?

A
When beetroot cells are placed in a solution with cellulase, the solution turns dark red.

B
When beetroot cells are placed in a solution with cellulase, the solution remains clear.

C
When beetroot cells are placed in a solution, it turns dark red with or without cellulase present.

D
Since plant cells contain cell membranes, not cell walls, the alternate hypothesis cannot be tested.