Final answer:
Short, fine, unpigmented, and downy hair is classified as vellus hair, which has different characteristics and functions compared to terminal and androgenic hair. The correct option is A.
Step-by-step explanation:
The type of hair that is short, fine, unpigmented, and downy is known as vellus hair. This type of hair is different from terminal hair, which is longer, coarser, and usually pigmented, as well as androgenic hair, which develops during and after puberty and is influenced by hormonal changes.
Vellus hair serves various functions, including providing a layer of insulation and helping in the regulation of body temperature.
Therefore, the correct option is A.