Answer:
None of the options in the multiple choice question accurately describes a coenzyme.
A coenzyme is an organic molecule that works together with an enzyme to facilitate a chemical reaction. It is not permanently attached to the enzyme, but instead binds temporarily to the enzyme's active site, often through non-covalent interactions.
Coenzymes are important in many biological processes, including metabolism and energy production, and they often act as carriers of electrons or functional groups between different enzymes or biochemical pathways.
Examples of coenzymes include vitamins such as niacin (which is part of the coenzyme NAD+) and riboflavin (which is part of the coenzyme FAD). Coenzymes can also be derived from other molecules, such as coenzyme A (derived from the vitamin pantothenic acid), which plays a key role in many metabolic reactions.