Which of the following is NOT a Class B narcotic?

Heroin is classified as a Class A narcotic under the Controlled Substances Act. This classification applies to substances that have a high potential for abuse and are considered illegal to possess or distribute without specific regulatory controls. In contrast, the other listed substances—cocaine, fentanyl, and codeine—are categorized within Class B narcotics, which also fall into the realm of controlled substances but do have legal uses under certain circumstances. For instance, while cocaine is often associated with unlawful use, it has recognized medical applications in anesthesia, and codeine is widely used in prescription medications. Fentanyl, although incredibly potent and also associated with abuse, is classified as a Class B narcotic due to its medical applications for severe pain management.

Thus, the answer indicates that heroin does not belong to the Class B category, marking it as the exception among the options presented.