Correct option is D
A. Vitamin A: Vitamin A (in the form of beta-carotene, a provitamin) is an antioxidant. It helps protect cells from oxidative stress by neutralizing free radicals. It's important for immune function, vision, and skin health.
B. Vitamin D: Vitamin D is not classified as an antioxidant. It plays a critical role in calcium absorption and bone health but does not have antioxidant properties.
C. Vitamin E: Vitamin E is a well-known antioxidant. It helps protect cell membranes from oxidative damage and is essential for maintaining the health of the skin and eyes.
D. Vitamin K: Vitamin K is important for blood clotting and bone health but is not classified as an antioxidant. It does not function as a free radical scavenger like vitamins A, C, and E.
E. Vitamin C: Vitamin C (ascorbic acid) is a powerful antioxidant that protects cells from oxidative stress. It is also crucial for collagen synthesis, immune function, and wound healing.