**Core Concept**
Sickle cell anemia is a genetic disorder caused by a mutation in the **HBB** gene, leading to the production of abnormal **hemoglobin S**. Hemoglobin electrophoresis is a diagnostic tool used to identify different types of hemoglobin in the blood.

**Why the Correct Answer is Right**
In sickle cell anemia, hemoglobin electrophoresis typically shows the presence of **hemoglobin S** and sometimes **hemoglobin F** or **hemoglobin A2**, but not **hemoglobin A** in homozygous individuals. The correct answer choice is not provided, but based on the context, it's likely related to the absence of a specific normal or abnormal hemoglobin variant.

**Why Each Wrong Option is Incorrect**
**Option A:** This choice is potentially incorrect because **hemoglobin S** is the primary abnormal hemoglobin seen in sickle cell anemia.
**Option B:** Similarly, **Option B** could be incorrect if it represents another hemoglobin variant that might be present, such as **hemoglobin F**.
**Option C:** Without the specific option details, it's challenging to address each directly, but typically, **hemoglobin A** would not be the primary component in homozygous sickle cell anemia, making any option suggesting its absence potentially correct.

**Why Each Wrong Option is Incorrect** (continued)
**Option D:** If this option represents **hemoglobin A**, it could be considered correct in the context of homozygous sickle cell anemia, where **hemoglobin A** is not seen.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that sickle cell anemia patients are typically homozygous for the **HbS** gene, leading to the presence of **hemoglobin S** and the absence of **hemoglobin A** on electrophoresis.

**Correct Answer:** D. Hemoglobin A