**Explanation:**

**Iron and Blood:**
Iron is an important mineral that our body needs to produce hemoglobin, a protein found in red blood cells (RBCs) that carries oxygen from the lungs to the rest of the body. When we consume iron-rich foods, the iron is absorbed into our bloodstream and used to produce more hemoglobin.

**Effect on Blood Components:**
The increase in iron levels from consuming iron-rich foods primarily affects the production of red blood cells (RBCs) and the hemoglobin within them.

**1. Red Blood Cells (RBCs):**
- RBCs are responsible for carrying oxygen to different parts of the body.
- Iron is a key component of hemoglobin, which gives RBCs their red color and enables them to bind to oxygen.
- When we consume iron-rich foods, the iron is absorbed into the body and used to produce more RBCs.
- This leads to an increase in the number of RBCs in our bloodstream.

**2. Hemoglobin:**
- Hemoglobin is a protein found inside RBCs that helps transport oxygen.
- When we consume iron-rich foods, the absorbed iron is used to synthesize more hemoglobin.
- An increase in iron levels leads to an increase in the production of hemoglobin.
- This, in turn, increases the oxygen-carrying capacity of our blood.

**Conclusion:**
In summary, when we eat iron-rich foods, the iron is absorbed into our bloodstream and used to produce more red blood cells (RBCs) and hemoglobin. This increase in iron levels leads to an increase in the number of RBCs and the amount of hemoglobin in our blood. Therefore, the correct answer to the question is option 'C' - Hemoglobin.