Which statement best captures a limitation of many commercial probiotic supplements highlighted in the lesson?

• A. They always permanently colonize the gut and therefore require only a single dose to replace dietary measures such as fiber intake for life.
• B. They are identical to fermented foods in composition and effect, so there is never any reason to consume whole fermented foods when supplements are available.
• C. They often deliver large quantities of one or a few strains, which may offer specific benefits but do not substitute for maintaining a naturally diverse microbiome supported by varied dietary fibers.
• D. They are universally harmful because any introduced microbe immediately causes inflammation and should never be used under any circumstances.

Answer: (C)