Which of the following is NOT a component of the central nervous system?

• A. Brain and spinal cord
• B. Peripheral nervous system
• C. Cerebral cortex
• D. Brainstem

Answer: (B)

The central nervous system is made up of the brain and spinal cord, where information is processed and integrated. The cerebral cortex is a major part of the brain, and the brainstem is the lower part of the brain connecting to the spinal cord; both reside inside the CNS. The peripheral nervous system, on the other hand, includes all nerves and ganglia outside the brain and spinal cord, serving as the link between the CNS and the rest of the body. Since the question asks for what is not a component of the CNS, the peripheral nervous system is the correct choice.