Which of the Following Situations Demonstrates the Risk of a Microbiome

Which of the following situations demonstrates the risk of a microbiome?

A) Mary suffers from colon cancer. While being treated, she develops an opportunistic Bacteroides fragilis infection.
B) Andy is lactose intolerant. His body does not break down lactose, so the microorganisms in the gut do it for him.
C) Jenna is prone to yeast infections, so she routinely eats yogurt and takes a probiotic supplement to increase the amount of lactic acid bacteria in her vagina.
D) Anthony suffers from debilitating diarrhea after a lengthy course of antibiotics to treat his MRSA infection.