What is the effect of the ∆32 allele of CCR5 on HIV binding?

A) appears on the surface of CD4 T cells, but the HIV virion is unable to infect the host cell
B) does not appear on the surface of CD4 T cells
C) appears on the surface of the CD4 T cells and inactivates the virion upon binding
D) interferes with binding of the virion to the CD4 receptor protein
E) appears on the surface of the CD4 T cells and causes the virion to lyse upon binding