**Core Concept**
The lymphatic drainage of the breast is a complex system that involves the axillary lymph nodes, which are primarily responsible for draining the breast tissue. The axillary lymph nodes are divided into five levels, and the level of involvement depends on the location of the primary tumor within the breast.

**Why the Correct Answer is Right**
The breast tissue drains lymph fluid into the axillary lymph nodes, which are located in the armpit. The lymph nodes that are most likely to be affected by a breast mass in the left breast are the axillary lymph nodes, specifically the level I and II nodes. These nodes are responsible for draining the lateral and central portions of the breast. The level I nodes include the pectoral group, lateral group, and anterior group, while the level II nodes include the posterior group. The surgeon will likely remove these nodes to assess for metastasis and to treat the cancer if necessary.

**Why Each Wrong Option is Incorrect**
* **Option A:** The supraclavicular lymph nodes are not the primary lymph nodes involved in breast cancer drainage. While they can be involved in advanced cases, they are not the first line of drainage for the breast tissue.
* **Option B:** The internal mammary lymph nodes can be involved in breast cancer drainage, but they are not the primary lymph nodes that would be affected by a mass in the left breast.
* **Option C:** The infraclavicular lymph nodes are located below the clavicle and are not the primary lymph nodes involved in breast cancer drainage.

**Clinical Pearl / High-Yield Fact**
When performing a breast examination, it's essential to note that the breast tissue drains lymph fluid into the axillary lymph nodes. Therefore, any masses or abnormalities in the breast should be evaluated for potential axillary lymph node involvement.

**Correct Answer: C. The level I and II axillary lymph nodes are most likely to be affected.**