What is pyrolysis?

A) The decomposition of a solid to form combustible, gaseous compounds.
B) The decomposition of a gas to form combustible, gaseous compounds.
C) The decomposition of a solid to form non-combustible materials.
D) The decomposition of a liquid to form non-combustible materials.

Pyrolysis is the thermal decomposition of materials at elevated temperatures in an inert atmosphere. It involves the change of chemical composition and is most commonly used to convert organic materials into combustible gases and a solid residue by heating them in the absence of oxygen, thus preventing combustion. This process is typically applied to solids, such as plastics or biomass, to produce energy or chemical products.