Which of the following types of skin is most likely to be sunburned?

Thin and white skin is the type most likely to be sunburned due to its reduced melanin content, which provides less natural protection from ultraviolet (UV) rays. Melanin is the pigment responsible for the color of skin, hair, and eyes, and it offers some level of defense against UV radiation by absorbing harmful rays and preventing DNA damage in skin cells.

In contrast, skin that is thick and dark in color typically has more melanin and is more resilient against sunburn. Dark and oily skin may also possess an inherent level of protection from UV exposure. Individuals with medium-toned and freckled skin may have varying sensitivity to sun exposure, but they generally have more natural pigmentation than individuals with thin and white skin, making them somewhat less susceptible to sunburn.

Overall, the inherent characteristics of the skin type better explain the likelihood of sunburn, with thin and white skin being the most vulnerable due to its lack of protective melanin.