**Core Concept**
Iron overload, also known as hemochromatosis, occurs when there is an excessive accumulation of iron in the body. This can be due to various causes, including genetic mutations, excessive dietary iron intake, or acquired conditions that lead to increased iron absorption.

**Why the Correct Answer is Right**
Iron overload can be caused by several acquired conditions, including **A. Thalassemia major**, which requires frequent blood transfusions leading to iron accumulation. **B. Sideroblastic anemia**, a group of disorders that cause the bone marrow to produce abnormal iron-containing mitochondria, resulting in iron overload. **C. Chronic liver disease**, such as cirrhosis, can lead to increased iron absorption and decreased iron excretion.

**Why Each Wrong Option is Incorrect**
**Option D:** **Hemochromatosis** is a genetic disorder that leads to iron overload, making it an inherited cause rather than an acquired cause.

**Clinical Pearl / High-Yield Fact**
It is essential to differentiate between inherited and acquired causes of iron overload, as treatment strategies and genetic counseling may vary.

**Correct Answer: D. Hemochromatosis**