Chuck Has Been Treated for HIV for More Than 20

Chuck has been treated for HIV for more than 20 years,and although he sometimes struggles with side effects,he is doing pretty well.Because of the development of resistance,his doctors are changing some of his medications and suggest raltegravir,an integrase inhibitor.How does this drug act?

A) It blocks entry of HIV into cells,which may keep the virus from reproducing.
B) It slows the advancement of HIV infection by blocking the enzyme needed for viral replication.
C) It inhibits an enzyme responsible for viral replication early in the viral life cycle.
D) It blocks a co-receptor required for HIV entry into human cells.