**Core Concept**
Modified apocrine glands are a type of apocrine sweat gland that are found in the axillary and anogenital regions. They are characterized by their ability to secrete a protein-rich, lipid-rich secretion that plays a role in pheromone production and antimicrobial defense.

**Why the Correct Answer is Right**
Modified apocrine glands are found in the axillary and anogenital regions, and are responsible for producing a unique type of secretion that contains proteins and lipids. This secretion is thought to play a role in pheromone production, and may also have antimicrobial properties. The apocrine glands are distinct from eccrine glands, which are found throughout the body and produce a clear, watery secretion.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify a type of apocrine gland. While apocrine glands are indeed found in the axillary and anogenital regions, not all apocrine glands are modified.
* **Option B:** This option is incorrect because it does not accurately describe the function of modified apocrine glands. While apocrine glands do produce a protein-rich secretion, their primary function is not pheromone production.
* **Option C:** This option is incorrect because it does not accurately describe the location of modified apocrine glands. While apocrine glands are found in the axillary and anogenital regions, they are not the only type of gland found in these areas.

**Clinical Pearl / High-Yield Fact**
Modified apocrine glands are an important part of the body's defense against infection, and play a role in the production of pheromones. They are also responsible for producing a unique type of secretion that contains proteins and lipids.

**Correct Answer: D.**