**Core Concept**
The femoral triangle is an anatomical region in the anterior thigh, demarcated by the inguinal ligament, the medial border of the sartorius muscle, and the medial border of the adductor longus muscle. It is a critical area for the examination of the femoral artery, vein, and nerve.

**Why the Correct Answer is Right**
The correct answer is **A. Femoral Artery**. The femoral artery is the medial most structure in the femoral triangle because it is located deep to the sartorius muscle, between the medial border of the sartorius and the medial border of the adductor longus muscle. This positioning allows the femoral artery to be palpated and examined in this region.

**Why Each Wrong Option is Incorrect**
* **Option B:** The femoral vein is located lateral to the femoral artery in the femoral triangle, making it the second medial structure.
* **Option C:** The femoral canal is a small, oval-shaped structure located medial to the femoral vein, but it is not the most medial structure in the femoral triangle.
* **Option D:** The lymph nodes of Cloquet, also known as Rosenmüller's node, are located in the femoral canal but are not the most medial structure in the femoral triangle.

**Clinical Pearl / High-Yield Fact**
In the femoral triangle, the femoral artery is the most medial structure, and it can be palpated between the medial border of the sartorius muscle and the medial border of the adductor longus muscle.

**Correct Answer:** A. Femoral Artery