Final answer:
The structure involved in emotions, memory, and behavior in the CNS is the Limbic System, which includes the hippocampus, amygdala, thalamus, cingulate gyrus, and hypothalamus. The correct answer is D).
Step-by-step explanation:
The central nervous system (CNS) structure that is involved in emotions, memory, and behavior is the D) Limbic System. The limbic system includes connected structures such as the hippocampus, amygdala, thalamus, and hypothalamus. These structures collaborate to regulate emotional responses, form memories, and drive various behaviors. For instance, the amygdala plays a key role in the perception of fear and in recognizing fearful expressions, while the hippocampus is vital for learning and memory formation.
The cingulate gyrus, which is also part of the limbic system, helps in regulating emotions and pain. Moreover, the limbic system's connections with the hypothalamus influence the autonomic system and the endocrine system, thereby affecting visceral responses and bodily homeostasis, linking emotions with physiological functions.