Hemoglobin S (HbS)is Formed in Sickle Cell Disease as a Result

Hemoglobin S (HbS) is formed in sickle cell disease as a result of which process?

A) Deficiency in glucose 6-phosphate dehydrogenase (G6PD) that changes hemoglobin A (HbA) to HbS.
B) Genetic mutation in which two amino acids (histidine and leucine) are missing.
C) Genetic mutation in which one amino acid (valine) is replaced by another (glutamic acid) .
D) Autoimmune response in which one amino acid (proline) is detected as an antigen by abnormal immunoglobulin G (IgG) .