Which Mechanisms Are Ways in Which Antibodies Can Protect the Body

Which mechanisms are ways in which antibodies can protect the body by either destroying or inactivating a particular antigen?

A) Mechanically harming the antigen
B) Activating the complement system
C) Releasing chemicals that alter the environment of the antigen
D) Directly attacking the nucleus of the antigen
E) Forming organic "chains" that sweep out the antigen