**Core Concept**
Measuring the mean corpuscular volume (MCV) and performing a peripheral smear (PS) are essential steps in diagnosing anemia, as they help differentiate between microcytic, normocytic, and macrocytic anemia.

**Why the Correct Answer is Right**
The presence of macrocytic RBCs with hypersegmented neutrophils on the PS is characteristic of megaloblastic anemia. This occurs when there is a deficiency in either vitamin B12 or folate, leading to impaired DNA synthesis and subsequent macrocytosis. The hypersegmented neutrophils are a hallmark of megaloblastic anemia, as they have more than 5 lobes, indicating an abnormal maturation process.

**Why Each Wrong Option is Incorrect**
**Option A:** While anemia of chronic disease (ACD) can present with fatigue and tiredness, it typically does not cause macrocytic RBCs or hypersegmented neutrophils. ACD is characterized by a normocytic or slightly microcytic anemia due to impaired iron mobilization.

**Option B:** Iron deficiency anemia (IDA) is characterized by microcytic RBCs, not macrocytic RBCs. IDA is the most common cause of anemia worldwide and is often associated with fatigue and tiredness.

**Option C:** Normocytic anemia can be seen in various conditions, including anemia of chronic disease, hemorrhage, or acute blood loss. However, it does not typically present with macrocytic RBCs or hypersegmented neutrophils.

**Clinical Pearl / High-Yield Fact**
When evaluating a patient with anemia, it's essential to remember that the MCV can help narrow down the differential diagnosis. Macrocytic anemia is often associated with megaloblastic anemia, while microcytic anemia is more commonly seen in iron deficiency or thalassemia.

**Correct Answer:** C. Megaloblastic anemia.