**Core Concept:** Vitamins are organic compounds essential for maintaining human health, particularly for various biochemical processes and prevention of diseases. Vitamin E is a fat-soluble antioxidant that plays a crucial role in protecting cell membranes and other biomolecules from damage caused by free radicals and reactive oxygen species (ROS).

**Why the Correct Answer is Right:** Vitamin E, specifically alpha-tocopherol, acts as a scavenger of free radicals and reactive oxygen species (ROS). It prevents autoxidation by neutralizing these harmful molecules, thereby maintaining cellular integrity and preventing oxidative damage to tissues.

**Why Each Wrong Option is Incorrect:**

A. Vitamin A: Vitamin A is essential for vision, immune system function, and cell growth, but it is not primarily involved in preventing autoxidation.

B. Vitamin C: Although Vitamin C is an antioxidant, it primarily neutralizes superoxide and hydroxyl radicals, not necessarily preventing autoxidation as effectively as Vitamin E.

C. Vitamin D: Vitamin D is crucial for bone health and calcium absorption but is not primarily involved in preventing autoxidation.

D. Vitamin K: Vitamin K is essential for blood clotting and bone health, but it does not play a significant role in preventing autoxidation.

**Clinical Pearl:** The correct answer, Vitamin E, is crucial for maintaining cardiovascular health and reducing the risk of chronic diseases like heart disease and cancer. A deficiency in Vitamin E can lead to xeroderma, neuropathy, and muscle weakness.

**Correct Answer:** Vitamin E (Option D)