**Core Concept**
Iron absorption is a critical process that occurs in the small intestine, particularly in the duodenum, to ensure adequate iron levels in the body. This process involves the reduction of ferric iron (Fe3+) to ferrous iron (Fe2+) by a specific enzyme, which enables its absorption.

**Why the Correct Answer is Right**
Iron absorption primarily occurs in the duodenum, where the acidic environment and the presence of reducing agents, such as ascorbic acid, facilitate the conversion of ferric iron to ferrous iron. This reduction is catalyzed by the enzyme duodenal cytochrome b (b2) reductase. The ferrous iron is then transported across the enterocyte membrane by the divalent metal transporter 1 (DMT1). Once inside the enterocyte, iron is stored as ferritin or transported to the bloodstream via the ferroportin transporter.

**Why Each Wrong Option is Incorrect**
**Option A:** The stomach is not the primary site for iron absorption, although it does contribute to the reduction of ferric iron to ferrous iron through the action of gastric acid and ascorbic acid.
**Option B:** The pancreas plays a crucial role in digestion, but it is not directly involved in iron absorption.
**Option C:** The liver is involved in iron storage and regulation, but it is not the primary site for iron absorption.

**Clinical Pearl / High-Yield Fact**
Iron deficiency is a common cause of anemia in individuals with gastrointestinal disorders, such as celiac disease or Crohn's disease, which can impair iron absorption.

**Correct Answer: C. Duodenum. The duodenum is the primary site for iron absorption.**