A well-child examination has been completed on a 1-year-old child who appeared slightly pale. The results of the routine CBC are as follows: hemoglobin, 7.8 mcg/dL; mean corpuscular volume, decreased; and red cell distribution width, elevated. The remainder of the CBC is normal. What would be the most likely cause of this child's anemia?
A) Thalassemia
B) Megaloblastic anemia
C) Iron deficiency
D) Lead poisoning