Arrange in the correct sequence these components of the mammalian immune system as it first responds to a pathogen.
I) Pathogen is destroyed.
II) Lymphocytes secrete antibodies.
III) Antigens from a pathogen bind to antigen receptors on lymphocytes.
IV) Lymphocytes specific to antigens from a pathogen become numerous.
V) Only memory cells remain.
a. I → III → II → IV → V
b. II → I → IV → III → V
c. IV → II → III → I → V
d. III → IV → II → I → V