Final answer:
The brain is divided into the A. cerebrum, cerebellum, and brain stem. The spinal cord, while part of the CNS, is not a subpart of the brain but a separate structure connected to the peripheral nervous system.
Step-by-step explanation:
The brain, a part of the central nervous system (CNS), is divided into the cerebrum, cerebellum, and brain stem. These three major parts of the brain are responsible for various functions that are vital to our daily living. The cerebrum is the largest part and is further divided into two hemispheres and four lobes: frontal, parietal, temporal, and occipital, each associated with different functions. The outer layer of the cerebrum, known as the cerebral cortex, is where most information processing occurs. The cerebellum is involved in the coordination of voluntary movements, balance, and posture. Lastly, the brain stem, which continues as the spinal cord, plays a crucial role in conducting messages to and from the brain, as well as housing basic life-sustaining functions.
The spinal cord itself is not part of the brain; rather, it is a separate structure that serves as a conduit between the brain and the peripheral nervous system. It's important to note that while the spinal cord is a critical component of the CNS, it is not one of the divisions of the brain proper. Thus, within the scope of this question, option A presents the accurate divisions of the brain: cerebrum, cerebellum, and brain stem.