Which of the following can be a homologous substitution for valine in hemoglobin?

In Many examples of Point Mutations The classic example is sickle-cell disease, which is caused by mutation of a single base out of the 3 x 109 in the genome, a T-to-A DNA substitution, which in turn results in an A-to-U change in the mRNA corresponding to the sixth codon of the b-globin gene. The altered codon specifies a different amino acid (valine rather than glutamic acid), and this causes a structural abnormality of the b-globin molecule leading to hemoglobin aggregation and red blood cell "sickling." Ref: Harper's Illustrated Biochemistry, 30E (2015) Pg no 460.