An 18 year old man is evaluated for possible immunodeficiency disease because of a life-long history of chronic lung infections, recurrent otitis media, and multiple episodes of bacterial meningitis. While total IgG is normal, the patient is found to have a selective deficiency of IgG2. An associated deficiency of which of the following other substances may produce anaphylaxis when blood products are given to such individuals?
C3 C4 IgA IgE