The major constituents of the fungal cell wall are chitin, glucans, and glycoproteins. Chitin is a structurally important component of the fungal cell wall located closest to the plasma membrane. 
So, the correct answer is 'Chitin'.

Explanation:
Fungal cells have a unique cell wall structure which provides them rigidity, shape, and protection against environmental stress. The fungal cell wall is composed of various macromolecules such as polysaccharides, proteins, and lipids.

Main component of fungal cell wall:
Chitin is the main component of the fungal cell wall. It is a polysaccharide consisting of N-acetylglucosamine (GlcNAc) subunits linked by β-1,4 glycosidic bonds. Chitin is a strong and insoluble polymer that provides structural integrity to the fungal cell wall.

Other components of fungal cell wall:
Apart from chitin, the fungal cell wall also contains other polysaccharides such as β-glucans, mannan, and galactomannan. These polysaccharides provide additional strength and stability to the cell wall. The composition and structure of the fungal cell wall vary among different fungal species, and it also changes during different stages of fungal growth and development.

Functions of fungal cell wall:
The fungal cell wall performs several important functions such as:

- Protection: It protects the fungal cell from mechanical damage, osmotic stress, and host immune response.
- Rigidity and shape: It provides rigidity and shape to the fungal cell.
- Cell-cell interaction: It plays a role in cell-cell interaction and communication.
- Nutrient acquisition: It facilitates nutrient uptake and exchange with the environment.

Conclusion:
In conclusion, the fungal cell wall is a complex and dynamic structure composed of various macromolecules. Chitin is the main component of the fungal cell wall, providing structural integrity and protection to the fungal cell. Understanding the composition and function of the fungal cell wall is essential for developing new antifungal drugs and controlling fungal infections.