**Core Concept**
The surgeon is evaluating the location of a breast lesion in relation to the anatomical boundaries of the breast. The anterior axillary line, in this context, is a reference point to determine the extent of the breast tissue.

**Why the Correct Answer is Right**
The lateral edge of normal breast tissue extends to the anterior axillary line. This is because the breast tissue is bounded by the pectoralis major muscle medially, the serratus anterior muscle anteriorly, and the latissimus dorsi muscle posteriorly. The anterior axillary line, which is a vertical line drawn on the body from the anterior edge of the axilla, marks the lateral limit of the breast tissue.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the lateral edge of normal breast tissue does not extend beyond the mid-axillary line. The breast tissue is typically contained within the axillary fold, which is the area between the mid-axillary line and the anterior axillary line.
* **Option B:** This option is incorrect because the lateral edge of normal breast tissue does not extend to the posterior axillary line. The posterior axillary line marks the lateral border of the latissimus dorsi muscle, which is posterior to the breast tissue.
* **Option C:** This option is incorrect because the lateral edge of normal breast tissue does not extend to the posterior border of the pectoralis major muscle. The pectoralis major muscle forms the medial boundary of the breast tissue, not the lateral boundary.

**Clinical Pearl / High-Yield Fact**
It is essential for surgeons to understand the anatomical boundaries of the breast when evaluating breast lesions. Knowledge of these boundaries helps in accurate localization and staging of breast cancer.

**Correct Answer:** C.