Stimulated B lymphocytes switch from the synthesis of membrane-bound to secreted antibody molecules by increasing the concentration of a subunit of the trimeric CstF complex that cleaves and polyadenylates mRNAs. How does this up-regulation of CstF bring about the production of soluble antibodies?

A) It favors a strong polyadenylation site in the immunoglobulin primary transcript, creating a longer antibody molecule that is secreted.
B) It activates a weak polyadenylation site in the immunoglobulin primary transcript and prevents splicing, creating a shorter molecule that is secreted.
C) It favors a strong polyadenylation site in the immunoglobulin primary transcript, creating a shorter antibody molecule that is secreted.
D) It activates a weak polyadenylation site in the immunoglobulin primary transcript, creating a longer antibody molecule that is secreted.
E) It favors a strong polyadenylation site in the immunoglobulin primary transcript, aborting translation and creating a shorter antibody molecule that is secreted.