The correct answer is option 4, Vitamin D. Vitamin D is unique because our body is able to produce it when our skin is exposed to sunlight. When UVB rays from the sunlight hit our skin, they trigger a reaction that converts a cholesterol compound in our body into Vitamin D. This process occurs in the skin cells and then the newly formed Vitamin D is transported to the liver and kidneys where it is converted into its active form. This ability to produce Vitamin D in our body is beneficial because it means that we can maintain adequate levels of this vitamin even if our diet lacks it. However, it`s important to note that excessive exposure to sunlight can lead to negative health effects, so it`s always recommended to seek a balance between sunlight exposure and sun protection.