The correct option is D Cannabinoids
Marijuana is an herbal drug that is made from the Cannabis plant. It contains chemicals called cannabinoids. Cannabinoids are found in the highest levels in the leaves and flowers of cannabis. These cannabinoids are the class of drugs that only affect the brain since the cannabinoid receptors are primarily located on nerve cells in the brain, spinal cord. But they are also found in some peripheral organs and tissues such as the spleen, white blood cells, endocrine gland and parts of the reproductive, gastrointestinal and urinary tracts. Cannabinoids regulate how cells communicate - how they send, receive, or process messages.