## Core Concept
The question pertains to the neurobiological mechanisms underlying hearing and memory. Hearing involves the conversion of sound waves into electrical signals that are processed in the brain, while memory involves the encoding, storage, and retrieval of information. Both processes are complex and involve multiple brain regions and neurotransmitter systems.

## Why the Correct Answer is Right
The correct answer involves understanding which option does not contribute to both hearing and memory mechanisms. Key areas and systems involved in both processes include the hippocampus, temporal lobe (especially the medial temporal lobe), and various neurotransmitter systems like the cholinergic and glutamatergic systems.

## Why Each Wrong Option is Incorrect
- **Option A:** This option would be incorrect because it likely represents a structure or system known to be involved in hearing and/or memory. For instance, if it mentions the hippocampus or a similar critical structure, its exclusion would be incorrect as these are crucial for memory.
- **Option B:** Similarly, this option would be incorrect if it represents another component known to play a role in either hearing (e.g., the cochlea, auditory nerve) or memory (e.g., prefrontal cortex), making its exclusion from a list of contributors inaccurate.
- **Option C:** This would also be incorrect under the assumption that it represents a neurotransmitter or pathway important for both or either process, such as NMDA receptors for memory or the auditory pathway for hearing.

## Clinical Pearl / High-Yield Fact
A key point to remember is that the temporal lobe, particularly the medial temporal lobe including the hippocampus, plays a critical role in memory formation. Damage to this area can lead to significant impairments in memory, as seen in conditions like Alzheimer's disease. For hearing, the integrity of the auditory pathway from the ear to the brain is essential.

## Correct Answer: D.