Cell wall of plants are made up of ‘cellulose’.
Plant cell walls are primarily made of cellulose, which is the most abundant macromolecule on Earth. Cellulose fibers are long, linear polymers of hundreds of glucose molecules. The cell wall surrounds the plasma membrane of plant cells and provides tensile strength and protection against mechanical and osmotic stress. It also allows cells to develop turgor pressure, which is the pressure of the cell contents against the cell wall.
Hence, the answer is cellulose. So, the correct option is (B)