**Core Concept**
Iron deficiency anemia is a condition characterized by a decrease in the production of hemoglobin due to insufficient iron availability. This results in a deficiency of hemoglobin in red blood cells, leading to various morphological changes.

**Why the Correct Answer is Right**
In iron deficiency anemia, the peripheral blood smear typically shows hypochromic microcytic red blood cells. This is due to the reduced amount of hemoglobin within the cells, resulting in a smaller cell size (microcytic) and a lighter color (hypochromic). The reduced iron availability also leads to an increase in the number of sideroblasts, which are immature red blood cells containing iron-loaded mitochondria.

**Why Each Wrong Option is Incorrect**
**Option A:** **Spherocytes** are typically seen in hereditary spherocytosis, not iron deficiency anemia.
**Option B:** **Schistocytes** are fragmented red blood cells often seen in microangiopathic hemolytic anemia, not iron deficiency anemia.
**Option C:** **Target cells** are seen in conditions like thalassemia and hemoglobinopathies, not iron deficiency anemia.

**Clinical Pearl / High-Yield Fact**
In iron deficiency anemia, the peripheral blood smear is often described as having a "banded" or "basket-weave" appearance due to the irregular distribution of hemoglobin within the red blood cells.

**Correct Answer:** D. Hypochromic microcytic red blood cells.