The correct option is
D All of the above
Integument is the skin (epidermis and dermis) and its derivatives. It is the outermost covering of body and forms a protective covering on the body. The integumentary system is the organ system that protects the body from various kinds of damage, such as loss of water or abrasion from outside. Integument also plays an important role in temperature regulation (thermoregulation). Hence, the correct option is 'D'.