The correct answer is D. Chemical transmitter.
Acetylcholine is a neurotransmitter, a chemical that allows nerve cells to communicate with each other. It is found in the brain, spinal cord, and muscles. Acetylcholine is responsible for a variety of functions, including muscle movement, learning, and memory.
A toxin is a poisonous substance that can cause illness or death. Vitamin C is a water-soluble vitamin that is essential for human health. It is involved in many important bodily functions, including the production of collagen, the absorption of iron, and the maintenance of a healthy immune system. An enzyme is a protein that catalyzes, or speeds up, chemical reactions.
Acetylcholine is not a toxin, vitamin C, or an enzyme. It is a neurotransmitter.