单选题 Which of the following hypothetical discoveries, if made, would cast MOST doubt on the most recent conclusions regarding the function of the human appendix?

• (A) After laboratory experiments, scientists discover evidence to reject the notion that the human appendix is a "vestigial" organ.
• (B) Certain animal species which had not previously been given attention are discovered to possess an appendix resembling that of humans.
• (C) Lymphoid tissue is discovered, after careful study, not to play a role in the recognition of foreign antigens in ingested material.
• (D) After re-examination of the evidence, ulcerative colitis is discovered to be caused by factors wholly unrelated to the human appendix.
• (E) It is discovered that in rabbits, hindgut fermentation does not require the presence of an organ acting as reservoir for bacteria.