A child with sickle cell anemia is prescribed the drug hydroxyurea. Which effect from the drug is expected?

A. Clean out obstructed vessels: Hydroxyurea does not act as a "drain cleaner" for current blockages; it is a preventative medication. B. Produce a hemoglobin that resists sickling: Hydroxyurea increases the production of fetal hemoglobin (HbF). Fetal hemoglobin does not sickle, which helps prevent the red blood cells from deforming and causing crises. C. Increase energy: While it may improve overall health by reducing crises, its primary pharmacological mechanism is not as a stimulant or energy booster. D. Decrease cardiomegaly: While it may reduce long-term strain on the heart by improving oxygenation, it does not directly treat an enlarged heart.