Final answer:
HAC stands for Hyperadrenocorticism, also known as Cushing's disease, which is a disorder characterized by the overproduction of cortisol, leading to physiological changes like hair loss and rapid weight gain, but it does not relate to acne.
Step-by-step explanation:
The correct answer to the question of what HAC stands for is D) Hyperadrenocorticism. Hyperadrenocorticism, also known as Cushing's disease, is a disorder characterized by the overproduction of cortisol by the adrenal glands. This condition can lead to several physiological changes, including high blood glucose levels, the accumulation of lipid deposits on the face and neck, rapid weight gain, and hair loss. It is important to note that although acne is a common skin condition associated with hormonal changes and infections of sebaceous glands, it is not related to the abbreviation HAC. Hyperadrenocorticism, not to be confused with acne or other skin and hair conditions, is specifically related to endocrine dysfunctions involving the adrenal glands.