The Ability of One Person to Produce Over a Million

The ability of one person to produce over a million different antibody molecules does not require over a million different genes;rather,this wide range of antibody production is due to

A) alternative splicing of exons after transcription.
B) increased rate of mutation in the RNA molecules.
C) rearrangements of randomly selected V and J coding fragments in DNA.
D) expression of different cytosolic proteins in the thymus cells.
E) crossing over between the light and heavy chains of each antibody molecule during meiosis I.