Different Individuals Can Have Different Numbers of Functional V Gene $\kappa$

Different individuals can have different numbers of functional V gene segments as well as different numbers of constant region genes. This type of genetic polymorphism between individuals indicates that:

A) The antibody heavy and light chain loci undergo more frequent mutation than other genes in the genome.
B) The recombination machinery is active in germ cells.
C) Individuals only need $\kappa$ or $\lambda$ light chains, but not both.
D) The precise number of antibody gene segments in an individual is not important.
E) Antibody gene segments underwent more frequent duplication during evolution than other genes in the genome.