What Is the Significance of the Gene Mutation in the Battle

What is the significance of the gene mutation in the battle against HIV?

A) People with two copies of the CCR5 gene mutation are resistant to infection.
B) People with two copies of the CCR5 gene mutation, if infected, show much slower disease progression.
C) The CCR5 gene mutation is much more common in Asia than in other parts of the world.
D) The CCR5 gene mutation has reduced the scope of gene therapy as a treatment procedure.