Hydroxyurea is a common drug treatment for sickle cell anemia patients. Hydroxyurea improves sickle cellsymptoms because it

A) causes more hemoglobin alpha chains to be produced improving oxygen transport.
B) causes more hemoglobin beta chains to be produced improving oxygen transport.
C) increases the free iron in plasma.
D) stimulates the production of fetal hemoglobin improving oxygen transport.
E) increases the production of heme.