Answer the following question given this paragraph: 

Crystalline solids are generally classified according the nature of the forces that hold its particles together. These forces are primarily responsible for the physical properties exhibited by the bulk solids. The following sections provide descriptions of the major types of crystalline solids: ionic, metallic, covalent network, and molecular.


Q: What kind of solids are generally classified by the forces that hold their particles together and include ionic, metallic, covalent network, and molecular types?

 Choices:

- distinct solids

- helium solids

- flat solids

- crystalline solids

A:
crystalline solids
