**Core Concept**
The femoral hernia occurs when part of the intestine protrudes through the femoral canal, a narrow passageway in the groin area. The femoral canal is bounded by the inguinal ligament (Poupart's ligament) laterally, the lacunar ligament (Gimbernat's ligament) medially, and the pectineal ligament (Cooper's ligament) inferiorly. The femoral hernia is classified as an indirect hernia because it passes through the femoral ring, which is an opening in the inguinal ligament.

**Why the Correct Answer is Right**
The base of the femoral hernia sac lies below and lateral to the pubic tubercle due to its anatomical location. The femoral canal is positioned below the inguinal ligament, which runs from the pubic tubercle to the anterior superior iliac spine (ASIS). The femoral hernia sac emerges through the femoral ring, which is located below and lateral to the pubic tubercle. This is a critical point for surgeons to identify the correct location of the hernia sac during surgical procedures.

**Why Each Wrong Option is Incorrect**
**Option B:** The base of the femoral hernia sac does not lie below and medial to the pubic tubercle, as the femoral canal is positioned laterally, not medially, relative to the pubic tubercle.

**Option C:** The base of the femoral hernia sac does not lie above and lateral to the pubic tubercle, as the femoral canal is positioned below the inguinal ligament, not above it.

**Option D:** The base of the femoral hernia sac does not lie above and medial to the pubic tubercle, as the femoral canal is positioned laterally, not medially, relative to the pubic tubercle.

**Clinical Pearl / High-Yield Fact**
To identify the base of the femoral hernia sac, surgeons should look for a bulge below and lateral to the pubic tubercle, which is a critical landmark for femoral hernia diagnosis and repair.

**✓ Correct Answer: A. Below and lateral**