Hemoglobin Is a Protein That Carries Oxygen in Red Blood

Hemoglobin is a protein that carries oxygen in red blood cells. The hemoglobin molecules produced by some people have one specific amino acid that is different from the amino acid at that position in normal hemoglobin.Which of the following is the most likely cause of this amino acid variation?

A) The hemoglobin gene contains a mutation.
B) An error occurs during the folding of the hemoglobin protein.
C) Enzymes replace the amino acid once the hemoglobin is produced.
D) An additional amino acid is mistakenly inserted into the hemoglobin during translation.