**Core Concept**
Vitamin E deficiency can lead to various neurological, hematological, and immunological manifestations due to its role in protecting cell membranes from oxidative damage and its involvement in the immune system.

**Why the Correct Answer is Right**
Vitamin E deficiency can cause ataxia, peripheral neuropathy, and impaired immune function, which are all related to its antioxidant properties and its role in maintaining the integrity of cell membranes. It also affects the hematological system, leading to increased susceptibility to infections and impaired wound healing. The correct answer will be the option that does not belong to this category.

**Why Each Wrong Option is Incorrect**
**Option A:** Ataxia is a known manifestation of vitamin E deficiency, which affects the posterior columns and spinocerebellar tracts of the spinal cord, leading to gait disturbances and impaired coordination.
**Option B:** Peripheral neuropathy is a common symptom of vitamin E deficiency, resulting from damage to the peripheral nerves and affecting motor and sensory functions.
**Option C:** Impaired immune function is a critical consequence of vitamin E deficiency, making individuals more susceptible to infections and affecting the overall immune response.

**Clinical Pearl / High-Yield Fact**
Vitamin E deficiency can be caused by malabsorption, genetic disorders, or increased oxidative stress, and it is essential to recognize its manifestations to initiate timely treatment and prevent long-term complications.

**Correct Answer: D.**