Correct Option: D

Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations. Catalysts that speed the reaction are called positive catalysts. Substances that slow a catalyst’s effect in a chemical reaction are called inhibitors. Substances that increase the activit y of catalysts are called promoters, and substances that deactivate catalysts are called catalytic poisons.