Which of the Following Is Used to Generate Diversity in the Antibody

Which of the following is used to generate diversity in the antibody repertoire?

A) Presence of multiple variable gene segments that can be assembled in multiple different combinations
B) Addition of N nucleotides that are not encoded in the germ line
C) Exonuclease trimming of excess nucleotides at variable segment junctions
D) Ability to pair a single heavy chain with different light chains, so as to avoid generation of autoreactive antibodies
E) All of the answers are correct.