**Core Concept**
The question requires understanding of neurodegenerative mechanisms and factors that contribute to neuronal damage or death. Neurodegeneration involves the progressive loss of structure or function of neurons, leading to various diseases such as Alzheimer's, Parkinson's, and Huntington's.

**Why the Correct Answer is Right**
The correct answer is the one that does not cause neurodegeneration. Neurodegeneration can be caused by various factors, including oxidative stress, excitotoxicity, mitochondrial dysfunction, and protein misfolding. For example, oxidative stress can lead to the formation of reactive oxygen species (ROS) that damage neuronal proteins and DNA. Excitotoxicity involves excessive activation of glutamate receptors, leading to neuronal damage and death.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because oxidative stress is a well-established cause of neurodegeneration.
**Option B:** This option is incorrect because excitotoxicity is a known mechanism of neurodegeneration, particularly in conditions such as stroke and traumatic brain injury.
**Option C:** This option is incorrect because mitochondrial dysfunction is a common feature of many neurodegenerative diseases, leading to impaired energy production and increased oxidative stress.

**Clinical Pearl / High-Yield Fact**
A key factor in neurodegeneration is the accumulation of misfolded proteins, which can lead to the formation of amyloid plaques and neurofibrillary tangles in diseases such as Alzheimer's. Understanding the mechanisms of neurodegeneration is crucial for developing effective treatments.

**Correct Answer: D.**