Cellulose is found throughout the cell walls of plant cells. cellulose makes cell walls rigid, which indicates that cellulose is a
carbohydrate.
lipid.
nucleic acid.
protein.

The correct answer is -  carbohydrate.

Explanation:

Cellulose is a structural component of the plants and the most found material of the earth. Cellulose is a straight link chain of the polysaccharides made up of the glucose molecules joined together by the β 1, 4 glycosidic bonds.

The glycosidic bond gives these carbohydrates a rigid and flat structure that makes cell walls of the plant rigid and act as structural components. These stack one upon another as they are flat and form hydrogen bond that provides extra rigidity to these components.

Thus, the correct answer is option - carbohydrate.