\(AlN\) is an example of

Covalent solid

The correct answer is option 2. Covalent solid.

Molecular solid: These solids are held together by weak intermolecular forces (van der Waals or hydrogen bonds) between individual molecules. \(AlN\) is not made up of discrete molecules, therefore it's not a molecular solid.

Covalent solid: These solids are characterized by strong covalent bonds between atoms throughout the entire crystal lattice. \(AlN\) forms strong covalent bonds between aluminum and nitrogen atoms, making it a covalent solid.

Metallic solid: These solids have a "sea of electrons" model, where delocalized electrons move freely throughout the lattice, holding the positively charged metal ions together. \(AlN\) does not have delocalized electrons and doesn't fit the characteristics of a metallic solid.

Ionic solid: These solids are held together by electrostatic attraction between ions of opposite charge. \(AlN\) does not have ionic bonds, as both aluminum and nitrogen lack the tendency to lose or gain electrons significantly.

Therefore, based on the strong covalent bonds between aluminum and nitrogen atoms, \(AlN\) is classified as a covalent solid.