Correct Answer:
D. Vitamin E.
Explanation:
The correct answer is Vitamin E. because 'tocopherol' is the formal biochemical designation for this group of essential fat-soluble antioxidants.
- Step 1 (Chemical Profile): Vitamin E comprises eight distinct organic compounds consisting of four tocopherols (alpha, beta, gamma, delta) and four tocotrienols, with alpha-tocopherol being the most biologically active form in humans.
- Step 2 (Physiological Utility): It plays an essential role inside the human body by scavenging free radicals, protecting cellular membranes from oxidative degradation, and supporting immune health.
- Incorrect Options:
- Vitamin A is incorrect because its formal biochemical names include retinol, retinal, and organic carotenoid pre-cursors.
- Vitamin C is incorrect because this vital water-soluble nutrient is chemically designated as ascorbic acid.
- Vitamin D is incorrect because its primary active biological forms are classified as cholecalciferol (D3) and ergocalciferol (D2).