Final answer:
Option (B), The primary characteristic of Fitzpatrick type 4 skin is that it easily tans, but it is still at risk for sun damage and skin cancer, so proper sun protection is necessary.
Step-by-step explanation:
The primary characteristic of Fitzpatrick type 4 skin is that it easily tans. This skin type rarely burns and tends to tan quite readily when exposed to the sun. It's important to understand that despite this tendency to tan rather than burn, there is still a risk of skin damage. Sunburn, caused by overexposure to UV-B and UV-C rays, can still occur if a person with Fitzpatrick type 4 skin is exposed to the sun for extended periods without proper protection.
The tanning response, while often thought to provide a level of protection against further sun exposure, is itself a sign of skin damage and can increase the risk of developing skin cancer. Therefore, even individuals with type 4 skin should take preventative measures, such as applying sunscreen and limiting sun exposure, to protect their skin from harmful UV damage.