Final answer:
Information entering the central nervous system is transmitted along afferent and sensory neurons, which are responsible for converting physical stimuli into nerve impulses headed towards the CNS.
Step-by-step explanation:
Information coming into the central nervous system is transmitted along afferent or sensory neurons, which carry nerve impulses from sensory receptors in tissues and organs to the central nervous system, converting physical stimuli like touch, light, and sound into nerve impulses. The term 'afferent' signifies that these neurons are bringing information toward the central nervous system. Therefore, the correct answer is D. afferent and sensory neurons. It's important to note that while all afferent neurons are sensory, not all sensory neurons are afferent, depending on the context being used, but in the context of this question referring to those carrying information to the central nervous system, they are synonymous.