**Core Concept**
The corpus callosum is a critical structure in the brain responsible for inter-hemispheric communication. Damage or involvement of the corpus callosum can lead to various neurological and cognitive impairments.

**Why the Correct Answer is Right**
Corpus callosum involvement on MRI is typically seen in conditions that cause demyelination, trauma, or tumors. One such condition is multiple sclerosis (MS), a chronic autoimmune disease characterized by the demyelination of nerve fibers in the central nervous system (CNS). In MS, the corpus callosum is often affected due to its large size and high myelin content, leading to the formation of lesions and subsequent damage.

**Why Each Wrong Option is Incorrect**
**Option A:** While Alzheimer's disease is a neurodegenerative disorder, it primarily affects the hippocampus and temporal lobe, rather than the corpus callosum.
**Option B:** Stroke or cerebral vasculitis can cause damage to the corpus callosum, but it is not the most common condition associated with corpus callosum involvement.
**Option C:** Tuberous sclerosis complex (TSC) is a genetic disorder that can cause neurodevelopmental disorders, but corpus callosum involvement is not a hallmark feature of the disease.

**Clinical Pearl / High-Yield Fact**
In clinical practice, corpus callosum involvement on MRI is often seen in conditions that cause demyelination or damage to the CNS. A high index of suspicion for MS should be maintained in patients presenting with corpus callosum lesions, particularly in the absence of other clear-cut diagnoses.

**Correct Answer:** D.