What types of materials fall under the category of "solid waste"?

Solid waste is defined as any discarded material that is not in a liquid or gaseous state. This includes a wide range of materials such as paper, plastics, metals, glass, and organic waste, among others. The category encompasses both hazardous and non-hazardous materials, as long as they are in solid form and set aside for disposal or treatment.

The definition excludes materials that are classified as liquids or gases, hence options that suggest inclusion of liquids or gases are not correct. Additionally, solid waste is not limited strictly to non-hazardous materials, as hazardous solid waste, such as certain industrial by-products and discarded chemicals, also falls under this category. Lastly, the definition is not restricted to organic materials alone, which only represent a fraction of the solid waste produced. Therefore, the correct understanding of solid waste encompasses all discarded solid materials, regardless of their hazardous status or composition.