Which type of UV rays penetrate deeper into the skin's subcutaneous layer?

UVA rays are known for their ability to penetrate the skin more deeply than other types of ultraviolet (UV) rays, such as UVB and UVC. The structure of these rays allows them to reach the dermis, which is the second layer of skin, and even reach into the subcutaneous layer. This capability is significant because UVA rays contribute to skin aging and the formation of wrinkles due to their deeper penetration.

In contrast, UVB rays primarily affect the outer layers of the skin, leading to sunburns but do not reach as deeply as UVA rays. UVC rays, while harmful, are generally absorbed by the Earth's atmosphere and do not reach the skin effectively. Therefore, when considering skin penetration, UVA is the primary concern due to its deeper reach into the skin layers, making it the correct answer to the question.