According to the National Heart and Lung Institute, sickle-cell anemia is a serious disorder in which the body makes sickle-shaped red blood cells. Sickle cells contain
abnormal hemoglobin that causes the cells to develop a sickle, or crescent, shape.
Sickle cells are stiff and sticky. They tend to block blood flow in the blood vessels of
the limbs and organs.

Based on the passage above, which of the following symptoms could be caused by
sickle-cell anemia?

A. Increased risk of infection and reduced ability to stop bleeding

B. Increased arterial plaques and reduced platelet production

C. Increased blood volume and reduced white blood cell production

D. Increased risk of stroke and reduced ability to exercise