Answer: B. beta
Step-by-step explanation:
Sickle cell anemia is a inherited disorder which occur due to mutation of gene responsible for synthesis of hemoglobin protein. Typically the gene which is responsible for synthesis of beta-globin protein which make the beta chains in the hemoglobin is affected by the mutation. As a result of this the red blood cells acquire a shape of sickle rather than round. Pain, cold, stress, dehydration and illness are the symptoms associated with this disorder.