In Rare Instances, B Cells Can Be Found That Have

In rare instances, B cells can be found that have two immunoglobulin light chain alleles, both of which are rearranged in frame, and can encode functional light chain proteins. Yet, on the surface of the B cell, only one of the two light chain proteins is detected in the membrane-bound immunoglobulin receptor. The reason these rare cells have two functional light chain rearrangements but only express one of the two light chains as part of the B-cell receptor is:

A) One of the two light chains is formed from rearrangement of a V gene segment that is a pseudogene.
B) One of the two light chain proteins doesn't form a stable complex with the heavy chain expressed in this cell.
C) One of the two light chain alleles is not transcribed efficiently, and produces only low levels of protein.
D) One of the two light chain alleles uses a V gene segment that is not targeted very often by the RAG recombinase.
E) One of the two light chains is rapidly degraded after synthesis due to improper folding.