**Core Concept**
Hereditary Spherocytosis (HS) is a genetic disorder characterized by the production of abnormal, sphere-shaped red blood cells (RBCs) that are prone to premature destruction. The underlying defect involves mutations in genes encoding proteins of the RBC membrane, leading to weakened membrane structure and increased susceptibility to hemolysis.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of Hereditary Spherocytosis. In HS, the RBC membrane is weakened due to mutations in genes encoding proteins such as spectrin, ankyrin, band 3, or protein 4.2. This leads to a loss of membrane surface area and a change in RBC shape, resulting in spherocytes. Spherocytes are more prone to hemolysis, especially in the spleen, where they are removed from the circulation. This process is known as splenic sequestration.

**Why Each Wrong Option is Incorrect**
**Option A:** Not a feature of Hereditary Spherocytosis. While Anemia is a common feature of HS, it is not a specific diagnostic criterion.

**Option B:** Actually seen in Hereditary Spherocytosis. Splenomegaly is a common feature of HS, resulting from the sequestration and destruction of spherocytes in the spleen.

**Option C:** Actually seen in Hereditary Spherocytosis. jaundice is a common feature of HS, resulting from the breakdown of hemoglobin from the destroyed spherocytes.

**Option D:** Actually seen in Hereditary Spherocytosis. Gallstones are a common feature of HS, resulting from the increased bilirubin production from the breakdown of hemoglobin.

**Clinical Pearl / High-Yield Fact**
A key feature of Hereditary Spherocytosis is the presence of spherocytes on the peripheral smear, which can be identified by their characteristic "basket handle" appearance.

**Correct Answer:** A.