**Core Concept**
Hesselbach's triangle is a significant anatomical landmark in the anterior abdominal wall, particularly in the context of inguinal hernias. It is a triangular space bounded by the inguinal ligament, the lateral margin of the rectus sheath, and the inferior epigastric vessels.

**Why the Correct Answer is Right**
Hesselbach's triangle is a crucial area for hernia repair, as hernias occurring in this region are more likely to be indirect inguinal hernias. The boundaries of Hesselbach's triangle are the inguinal ligament (Poupart's ligament) medially, the lateral margin of the rectus sheath laterally, and the inferior epigastric vessels superiorly. The correct boundaries of Hesselbach's triangle are essential for surgeons to identify and repair hernias effectively.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the inguinal ligament is indeed one of the boundaries of Hesselbach's triangle.

**Option B:** This option is incorrect because the lateral margin of the rectus sheath is also a recognized boundary of Hesselbach's triangle.

**Option C:** This option is incorrect because the inferior epigastric vessels are accurately described as a boundary of Hesselbach's triangle.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that Hesselbach's triangle is a key area for inguinal hernia repair, and the correct identification of its boundaries is crucial for effective hernia surgery. Surgeons should be aware of the anatomy of Hesselbach's triangle to avoid complications and ensure successful outcomes.

**Correct Answer: A.**