**Core Concept**
The sentinel lymph node (SLN) is the first lymph node to receive drainage from a primary tumor site. It plays a crucial role in cancer staging and treatment planning. The concept of the SLN is based on the idea that cancer cells from the primary tumor site will first spread to the lymphatic vessels and then to the nearest lymph node.

**Why the Correct Answer is Right**
The term "sentinel lymph node" was first used by Gould in 1960 to describe the first lymph node that received drainage from a primary tumor site. This concept is based on the idea that cancer cells will first spread to the lymphatic vessels and then to the nearest lymph node, making the SLN a crucial marker for cancer staging and treatment planning. The identification of the SLN is typically done using a radioactive tracer or a blue dye, which is injected near the primary tumor site and then tracked to the nearest lymph node.

**Why Each Wrong Option is Incorrect**
**Option A:** The term "sentinel lymph node" was first used by none of the above options, as the correct answer is Gould.
**Option B:** While the concept of cancer spread through lymphatic vessels is correct, the term "sentinel lymph node" was not first used by Morton.
**Option C:** The concept of lymph node involvement in cancer is correct, but the term "sentinel lymph node" was not first used by Cabanas.

**Clinical Pearl / High-Yield Fact**
The sentinel lymph node biopsy is a minimally invasive procedure that can help avoid unnecessary lymph node dissections and reduce the risk of lymphedema in patients with cancer.

**Correct Answer: C. Cabanas.