Several strains of the human papillomavirus (HPV)can cause cervical cancer in some women.In 2006,a vaccine against several of the cancer-causing HPV strains was released.If a mutation occurs in the virus resulting in antigenic variation,the vaccine may no longer be effective because

A)the presented antigens will no longer be able to bind to mast cells.
B)effector cells produced by the vaccine do not recognize the new strain.
C)memory cells produced by the vaccine do not recognize the new strain.
D)the cell wall of the new virus is impermeable to the vaccine.
E)the new virus is drug-resistant.