The correct answer to the question is option 2, chitin. The cell wall of a fungus is composed of chitin, which is a complex polysaccharide made up of repeating units of N-acetylglucosamine. Chitin provides structural support and protection to fungal cells. It is a tough and flexible material, similar to the exoskeleton of arthropods like insects and crustaceans.

Option 1, cellulose, is incorrect because cellulose is the main component of plant cell walls, not fungal cell walls. It is a polysaccharide made up of glucose units linked together, providing rigidity and strength to plant cells.

Option 3, cholesterol, is incorrect because cholesterol is not found in fungal cell walls. Cholesterol is a lipid that is primarily found in animal cell membranes, where it helps maintain membrane fluidity.

Option 4, glycogen, is incorrect because glycogen is a storage form of glucose in animals and some fungi, but it is not the main component of fungal cell walls. Fungal cell walls mainly consist of chitin, as mentioned earlier.