You've Forgotten What Happens After Sensitization, So Your Friend Gives

You've forgotten what happens after sensitization, so your friend gives you a summary. Which is the CORRECT statement?

A) Complement protein C3a binds to two IgE molecules bound to the surface of the basophil, causing it to degranulate and release histamine and other mediators.
B) On second  exposure, complement protein C3a binds to two IgG molecules attached to the surface of the mast cell, causing it to degranulate and release interleukins.
C) On second exposure, complement protein C5b cross-links two allergen molecules bound to the surface of the basophil, causing it to degranulate and release histamine and other mediators.
D) On second exposure, the allergen cross-links two IgE antibodies bound to the surface of the basophil, causing it to degranulate and release histamine and other mediators.
E) Second exposure to the allergen causes activation of B cells that are initially programmed to produce IgM molecules, but then undergo class switching to produce IgE.