Skin cancer is to exposure to the uv radiation as
a keratin is to tanning
b acne is to excessive secretion of oil
c waterproofing is to temperature regulation
d melanin is to acne

The correct answer is B. Acne is to excessive secretion of oil

Explanation:

Exposure to UV radiation is a common cause of skin cancer because excessive exposure to UV radiation leads to damage in the DNA of skin cells and this can cause abnormal growth of cells known as cancer. This implies UV radiation is related to cancer because it is a common cause.

Similarly, in acne skin condition in which follicles become clogged) one of the most common causes is the excessive secretion of oil. This implies as UV radiation causes skin cancer, excessive secretion of oil causes acne, and therefore acne and secretion of oil show a similar relationship like the one between UV radiation and skin cancer. Thus, skin cancer is to exposure to the UV radiation as "acne is to excessive secretion of oil".

the answer is

c. parental