Recombination Signal Sequences Are Conserved Heptamer and Nonamer Sequences That $\kappa$

Recombination signal sequences are conserved heptamer and nonamer sequences that flank the V, J, and D gene segments which undergo recombination to generate the final V region coding exon. Some of these have 12-nucleotide spacers between the heptamer and nonamer, and others have 23-nucleotide spacers. The reason recombination signal sequences come in these two forms is:

A) To ensure the correct assembly of gene segments so that a V_H recombines to a D_H and not to another V_H, for instance
B) To ensure that the heptamer and nonamer are found on the same face of the DNA double helix
C) To ensure that $\kappa$ , $\lambda$ , and heavy chains recombine within a locus and not between loci
D) To ensure that $\kappa$ , $\lambda$ , and heavy chain gene segments do not undergo recombination with non-immunoglobulin genes
E) To ensure that the RAG recombinase cuts the DNA between the last nucleotide of the heptamer and the coding sequence