Answer:
The correct answer would be D. epithelial tissue.
Epithelial tissue is a type of tissue which covers all the surface of the body.
It is present on the skin, blood vessels, urinary tract, and organs.
Thus, they cover the body surface, line all the body cavities as well as hollow organs. In addition, it also helps in forming glands.
It performs various functions in the body such as protection, selective absorption, secretion, transcellular transport, and sensing.