Final answer:
Vitamin E (option d) helps protect the skin from the harmful effects of UV radiation due to its antioxidant properties. While vitamins A, C, and D have various health benefits, they are not primarily known for direct UV protection.
Step-by-step explanation:
The vitamin that helps protect the skin from the harmful effects of the sun's UV light is vitamin E. Vitamin E has antioxidant properties which may help protect the skin from damage caused by free radicals and UV radiation. While vitamin D is produced in the skin in response to UVB radiation and is essential for bone health, it does not provide the same protective effects against sun damage as vitamin E.
Vitamin C is also known for its antioxidant properties but is more commonly associated with immune function and skin healing rather than direct sun protection. On the other hand, vitamin A is important for vision and immune function and does play a role in skin health but not specifically in sun protection. Therefore, for shielding skin against UV radiation, vitamin E would be the most relevant.