The cell wall of plant cells has a protective and supportive role. Its supporting role can maintain cell shape and control cell growth. The cell wall increases the mechanical strength of the cell and withstands the expansion of the internal protoplasts due to water absorption by the vacuoles. Pressure, so that the cells have a certain shape. The main function of the cell membrane is to protect and control the entry and exit of substances. It can be seen that A conforms to the meaning of the question.

So choose: A