Cellulose is a polysaccharide of β-glucose which is mainly used by organisms such as plants to conform its cellular walls, to maintain their form and structure. This molecule, which is composed of carbon, hydrogen, and oxygen atoms, can also consist of too many monomers, from a few to almost thousands of them, and can give that rigidity to the cell because of the strength of their chemical links. Having this clear, we can say that the correct answer is the first one: A. Component of cell walls.