**Core Concept**
Spherocytosis of red blood cells (RBCs) refers to the abnormal shape of RBCs, where they transform into sphere-like structures. This condition is often associated with hemolytic anemias, where the RBCs are destroyed faster than they can be produced by the bone marrow.

**Why the Correct Answer is Right**
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a genetic disorder that affects the enzyme G6PD, which is crucial for the proper functioning of RBCs. In G6PD deficiency, the enzyme is either absent or deficient, leading to an inability to maintain the normal shape and structure of RBCs. This results in the formation of spherocytes, which are more prone to hemolysis due to their increased surface-to-volume ratio. The oxidative stress caused by G6PD deficiency further exacerbates the hemolysis of spherocytes.

**Why Each Wrong Option is Incorrect**
**Option B:** Sickle cell anemia is characterized by the production of abnormal hemoglobin, leading to the deformation of RBCs into a sickle shape, but it does not typically result in spherocytosis.

**Option C:** Chronic myeloid leukemia (CML) is a type of cancer affecting the white blood cells, and it is not directly associated with spherocytosis of RBCs.

**Clinical Pearl / High-Yield Fact**
It is essential to note that G6PD deficiency can be triggered by various factors, including certain medications, infections, and foods, which can lead to a hemolytic crisis. Therefore, it is crucial to recognize this condition and take appropriate measures to prevent further hemolysis.

**Correct Answer:**
✓ Correct Answer: A. G6PD deficiency