The correct option is D All of the above
In molecular solids, molecules are the constituent particle. They are held together by both intramolecular bond and intermolecular force.
Molecular solids formed by non-polar covalent bonds are called non-polar molecular solids.
Monatomic gases such as He,Ar and homo diatomic molecules like Cl2,H2,I2 formed by non-polar covalent bond are non-polar molecular solids. These solids show the following characteristics:
(a) Being covalent, bonded by weak forces, they have low melting point and are usually in liquid or gases at room temperature and pressure.
(b) Atoms or molecules are held by weak dispersion force or London force
(c) Being non-polar, they are non-conductor of electricity.
Hence, option (d) is correct.