**Core Concept:** The question is asking about the anatomy of the breast, which is a part of the female reproductive system responsible for producing milk for lactation. The breast is composed of multiple structures including the lobes, alveoli, and ducts.

**Why the Correct Answer is Right:** The correct answer, D, refers to the breast as "mammary gland". The mammary gland is a key component of the breast, responsible for producing milk during pregnancy and lactation. The mammary gland is comprised of lobes and alveoli, which are essential for milk production.

**Why Each Wrong Option is Incorrect:**
A. **Breast cancer:** This is a disease affecting the breast, not an anatomic description of the breast.
B. **Breast feeding:** This is a function of the breast, not its anatomy.
C. **Breast tissue:** This is a broad term describing the overall composition of the breast, but does not encompass the key structures for milk production like the mammary gland does.

**Clinical Pearl / High-Yield Fact:**
A key clinical pearl here is to know that the mammary gland, despite being part of the breast, is distinct from breast cancer. Understanding the anatomy and function of the mammary gland is essential for understanding breast diseases and their management.

**Correct Answer:** **D. Mammary gland** - The mammary gland is the correct term for describing the primary functional unit of the breast responsible for milk production during pregnancy and lactation. The mammary gland is composed of lobes and alveoli, which are essential for milk production.